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Exploring the Excel Services REST API

- by jamiet

Over the last few years Analysis Services guru Chris Webb and I have been on something of a crusade to enable better access to data that is locked up in countless Excel workbooks that litter the hard drives of enterprise PCs. The most prominent manifestation of that crusade up to now has been a forum thread that Chris began on Microsoft Answers entitled Excel Web App API? Chris began that thread with: I was wondering whether there was an API for the Excel Web App? Specifically, I was wondering if it was possible (or if it will be possible in the future) to expose data in a spreadsheet in the Excel Web App as an OData feed, in the way that it is possible with Excel Services? Up to recently the last 10 words of that paragraph "in the way that it is possible with Excel Services" had completely washed over me however a comment on my recent blog post Thoughts on ExcelMashup.com (and a rant) by Josh Booker in which Josh said: Excel Services is a service application built for sharepoint 2010 which exposes a REST API for excel documents. We're looking forward to pros like you giving it a try now that Office365 makes sharepoint more easily accessible. Can't wait for your future blog about using REST API to load data from Excel on Offce 365 in SSIS. made me think that perhaps the Excel Services REST API is something I should be looking into and indeed that is what I have been doing over the past few days. And you know what? I'm rather impressed with some of what Excel Services' REST API has to offer. Unfortunately Excel Services' REST API also has one debilitating aspect that renders this blog post much less useful than it otherwise would be; namely that it is not publicly available from the Excel Web App on SkyDrive. Therefore all I can do in this blog post is show you screenshots of what the REST API provides in Sharepoint rather than linking you directly to those REST resources; that's a great shame because one of the benefits of a REST API is that it is easily and ubiquitously demonstrable from a web browser. Instead I am hosting a workbook on Sharepoint in Office 365 because that does include Excel Services' REST API but, again, all I can do is show you screenshots. N.B. If anyone out there knows how to make Office-365-hosted spreadsheets publicly-accessible (i.e. without requiring a username/password) please do let me know (because knowing which forum on which to ask the question is an exercise in futility). In order to demonstrate Excel Services' REST API I needed some decent data and for that I used the World Tourism Organization Statistics Database and Yearbook - United Nations World Tourism Organization dataset hosted on Azure Datamarket (its free, by the way); this dataset "provides comprehensive information on international tourism worldwide and offers a selection of the latest available statistics on international tourist arrivals, tourism receipts and expenditure" and you can explore the data for yourself here. If you want to play along at home by viewing the data as it exists in Excel then it can be viewed here. Let's dive in. The root of Excel Services' REST API is the model resource which resides at: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model Note that this is true for every workbook hosted in a Sharepoint document library - each Excel workbook is a RESTful resource. (Update: Mark Stacey on Twitter tells me that "It's turned off by default in onpremise Sharepoint (1 tickbox to turn on though)". Thanks Mark!) The data is provided as an ATOM feed but I have Firefox's feed reading ability turned on so you don't see the underlying XML goo. As you can see there are four top level resources, Ranges, Charts, Tables and PivotTables; exploring one of those resources is where things get interesting. Let's take a look at the Tables Resource: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables Our workbook contains only one table, called ‘Table1’ (to reiterate, you can explore this table yourself here). Viewing that table via the REST API is pretty easy, we simply append the name of the table onto our previous URI: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1') As you can see, that quite simply gives us a representation of the data in that table. What you cannot see from this screenshot is that this is pure HTML that is being served up; that is all well and good but actually we can do more interesting things. If we specify that the data should be returned not as HTML but as: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1')?$format=image then that data comes back as a pure image and can be used in any web page where you would ordinarily use images. This is the thing that I really like about Excel Services’ REST API – we can embed an image in any web page but instead of being a copy of the data, that image is actually live – if the underlying data in the workbook were to change then hitting refresh will show a new image. Pretty cool, no? The same is true of any Charts or Pivot Tables in your workbook - those can be embedded as images too and if the underlying data changes, boom, the image in your web page changes too. There is a lot of data in the workbook so the image returned by that previous URI is too large to show here so instead let’s take a look at a different resource, this time a range: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15') That URI returns cells A1 to C15 from a worksheet called “Data”: And if we ask for that as an image again: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15')?$format=image Were this image resource not behind a username/password then this would be a live image of the data in the workbook as opposed to one that I had to copy and upload elsewhere. Nonetheless I hope this little wrinkle doesn't detract from the inate value of what I am trying to articulate here; that an existing image in a web page can be changed on-the-fly simply by inserting some data into an Excel workbook. I for one think that that is very cool indeed! I think that's enough in the way of demo for now as this shows what is possible using Excel Services' REST API. Of course, not all features work quite how I would like and here is a bulleted list of some of my more negative feedback: The URIs are pig-ugly. Are "_vti_bin" & "ExcelRest.aspx" really necessary as part of the URI? Would this not be better: http://server/Documents/TourismExpenditureInMillionsOfUSD.xlsx/Model/Tables(‘Table1’) That URI provides the necessary addressability and is a lot easier to remember. Discoverability of these resources is not easy, we essentially have to handcrank a URI ourselves. Take the example of embedding a chart into a blog post - would it not be better if I could browse first through the document library to an Excel workbook and THEN through the workbook to the chart/range/table that I am interested in? Call it a wizard if you like. That would be really cool and would, I am sure, promote this feature and cut down on the copy-and-paste disease that the REST API is meant to alleviate. The resources that I demonstrated can be returned as feeds as well as images or HTML simply by changing the format parameter to ?$format=atom however for some inexplicable reason they don't return OData and no-one on the Excel Services team can tell me why (believe me, I have asked). $format is an OData parameter however other useful parameters such as $top and $filter are not supported. It would be nice if they were. Although I haven't demonstrated it here Excel Services' REST API does provide a makeshift way of altering the data by changing the value of specific cells however what it does not allow you to do is add new data into the workbook. Google Docs allows this and was one of the motivating factors for Chris Webb's forum post that I linked to above. None of this works for Excel workbooks hosted on SkyDrive This blog post is as long as it needs to be for a short introduction so I'll stop now. If you want to know more than I recommend checking out a few links: Excel Services REST API documentation on MSDNSo what does REST on Excel Services look like??? by Shahar PrishExcel Services in SharePoint 2010 REST API Syntax by Christian Stich. Any thoughts? Let's hear them in the comments section below! @Jamiet

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Lessons from rewriting POP Forums for MVC, open source-like

- by Jeff

It has been a ton of work, interrupted over the last two years by unemployment, moving, a baby, failing to sell houses and other life events, but it's really exciting to see POP Forums v9 coming together. I'm not even sure when I decided to really commit to it as an open source project, but working on the same team as the CodePlex folks probably had something to do with it. Moving along the roadmap I set for myself, the app is now running on a quasi-production site... we launched MouseZoom last weekend. (That's a post-beta 1 build of the forum. There's also some nifty Silverlight DeepZoom goodness on that site.)I have to make a point to illustrate just how important starting over was for me. I started this forum thing for my sites in old ASP more than ten years ago. What a mess that stuff was, including SQL injection vulnerabilities and all kinds of crap. It went to ASP.NET in 2002, but even then, it felt a little too much like script. More than a year later, in 2003, I did an honest to goodness rewrite. If you've been in this business of writing code for any amount of time, you know how much you hate what you wrote a month ago, so just imagine that with seven years in between. The subsequent versions still carried a fair amount of crap, and that's why I had to start over, to make a clean break. Mind you, much of that crap is still running on some of my production sites in a stable manner, but it's a pain in the ass to maintain.So with that clean break, there is much that I have learned. These are a few of those lessons, in no particular order...Avoid shiny object syndromeOver the years, I've embraced new things without bothering to ask myself why. I remember spending the better part of a year trying to adapt this app to use the membership and profile API's in ASP.NET, just because they were there. They didn't solve any known problem. Early on in this version, I dabbled in exotic ORM's, even though I already had the fundamental SQL that I knew worked. I bloated up the client side code with all kinds of jQuery UI and plugins just because, and it got in the way. All the new shiny can be distracting, and I've come to realize that I've allowed it to be a distraction most of my professional life.Just query what you needI've spent a lot of time over-thinking how to query data. In the SQL world, this means exotic joins, special caches, the read-update-commit loop of ORM's, etc. There are times when you have to remind yourself that you aren't Facebook, you'll never be Facebook, and that databases are in fact intended to serve data. In a lot of projects, back in the day, I used to have these big, rich data objects and pass them all over the place, through various application tiers, when in reality, all I needed was some ID from the entity. I try to be mindful of how many queries hit the database on a given request, but I don't obsess over it. I just get what I need.Don't spend too much time worrying about your unit testsIf you've looked at any of the tests for POP Forums, you might offer an audible WTF. That's OK. There's a whole lot of mocking going on. In some cases, it points out where you're doing too much, and that's good for improving your design. In other cases it shows where your design sucks. But the biggest trap of unit testing is that you worry it should be prettier. That's a waste of time. When you write a test, in many cases before the production code, the important part is that you're testing the right thing. If you have to mock up a bunch of stuff to test the outcome, so be it, but it's not wasted time. You're still doing up the typical arrange-action-assert deal, and you'll be able to read that later if you need to.Get back to your HTTP rootsASP.NET Webforms did a reasonably decent job at abstracting us away from the stateless nature of the Web. A lot of people criticize it, but I think it all worked pretty well. These days, with MVC, jQuery, REST services, and what not, we've gone back to thinking about the wire. The nuts and bolts passing between our Web browser and server matters. This doesn't make things harder, in my opinion, it makes them easier. There is something incredibly freeing about how we approach development of Web apps now. HTTP is a really simple protocol, and the stuff we push through it, in particular HTML and JSON, are pretty simple too. The debugging points are really easy to trap and trace.Premature optimization is prematureI'll go back to the data thing for a moment. I've been known to look at a particular action or use case and stress about the number of calls that are made to the database. I'm not suggesting that it's a bad thing to keep these in mind, but if you worry about it outside of the context of the actual impact, you're wasting time. For example, I query the database for last read times in a forum separately of the user and the list of forums. The impact on performance barely exists. If I put it under load, exceeding the kind of load I expect, it still barely has an impact. Then consider it only counts for logged in users. The context of this "inefficient" action is that it doesn't matter. Did I mention I won't be Facebook?Solve your own problems firstThis is another trap I've fallen into. I've often thought about what other people might need for some feature or aspect of the app. In other words, I was willing to make design decisions based on non-existent data. How stupid is that? When I decided to truly open source this thing, building for myself first was a stated design goal. This app has to server the audiences of CoasterBuzz, MouseZoom and other sites first. In this development scenario, you don't have access to mountains of usability studies or user focus groups. You have to start with what you know.I'm sure there are other points I could make too. It has been a lot of fun to work on, and I look forward to evolving the UI as time goes on. That's where I hope to see more magic in the future.

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Creating an SMF service for mercurial web server

- by Chris W Beal

I'm working on a project at the moment, which has a number of contributers. We're managing the project gate (which is stand alone) with mercurial. We want to have an easy way of seeing the changelog, so we can show management what is going on. Luckily mercurial provides a basic web server which allows you to see the changes, and drill in to change sets. This can be run as a daemon, but as it was running on our build server, every time it was rebooted, someone needed to remember to start the process again. This is of course a classic usage of SMF. Now I'm not an experienced person at writing SMF services, so it took me 1/2 an hour or so to figure it out the first time. But going forward I should know what I'm doing a bit better. I did reference this doc extensively. Taking a step back, the command to start the mercurial web server is $ hg serve -p <port number> -d So we somehow need to get SMF to run that command for us. In the simplest form, SMF services are really made up of two components. The manifest Usually lives in /var/svc/manifest somewhere Can be imported from any location The method Usually live in /lib/svc/method I simply put the script straight in that directory. Not very repeatable, but it worked Can take an argument of start, stop, or refresh Lets start with the manifest. This looks pretty complex, but all it's doing is describing the service name, the dependencies, the start and stop methods, and some properties. The properties can be by instance, that is to say I could have multiple hg serve processes handling different mercurial projects, on different ports simultaneously Here is the manifest I wrote. I stole extensively from the examples in the Documentation. So my manifest looks like this $ cat hg-serve.xml <?xml version="1.0"?> <!DOCTYPE service_bundle SYSTEM "/usr/share/lib/xml/dtd/service_bundle.dtd.1"> <service_bundle type='manifest' name='hg-serve'> <service name='application/network/hg-serve' type='service' version='1'> <dependency name='network' grouping='require_all' restart_on='none' type='service'> <service_fmri value='svc:/milestone/network:default' /> </dependency> <exec_method type='method' name='start' exec='/lib/svc/method/hg-serve %m' timeout_seconds='2' /> <exec_method type='method' name='stop' exec=':kill' timeout_seconds='2'> </exec_method> <instance name='project-gate' enabled='true'> <method_context> <method_credential user='root' group='root' /> </method_context> <property_group name='hg-serve' type='application'> <propval name='path' type='astring' value='/src/project-gate'/> <propval name='port' type='astring' value='9998' /> </property_group> </instance> <stability value='Evolving' /> <template> <common_name> <loctext xml:lang='C'>hg-serve</loctext> </common_name> <documentation> <manpage title='hg' section='1' /> </documentation> </template> </service> </service_bundle> So the only things I had to decide on in this are the service name "application/network/hg-serve" the start and stop methods (more of which later) and the properties. This is the information I need to pass to the start method script. In my case the port I want to start the web server on "9998", and the path to the source gate "/src/project-gate". These can be read in to the start method. So now lets look at the method scripts $ cat /lib/svc/method/hg-serve #!/sbin/sh # # # Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. # # Standard prolog # . /lib/svc/share/smf_include.sh if [ -z $SMF_FMRI ]; then echo "SMF framework variables are not initialized." exit $SMF_EXIT_ERR fi # # Build the command line flags # # Get the port and directory from the SMF properties port=`svcprop -c -p hg-serve/port $SMF_FMRI` dir=`svcprop -c -p hg-serve/path $SMF_FMRI` echo "$1" case "$1" in 'start') cd $dir /usr/bin/hg serve -d -p $port ;; *) echo "Usage: $0 {start|refresh|stop}" exit 1 ;; esac exit $SMF_EXIT_OK This is all pretty self explanatory, we read the port and directory using svcprop, and use those simply to run a command in the start case. We don't need to implement a stop case, as the manifest says to use "exec=':kill'for the stop method. Now all we need to do is import the manifest and start the service, but first verify the manifest # svccfg verify /path/to/hg-serve.xml If that doesn't give an error try importing it # svccfg import /path/to/hg-serve.xml If like me you originally put the hg-serve.xml file in /var/svc/manifest somewhere you'll get an error and told to restart the import service svccfg: Restarting svc:/system/manifest-import The manifest being imported is from a standard location and should be imported with the command : svcadm restart svc:/system/manifest-import # svcadm restart svc:/system/manifest-import and you're nearly done. You can look at the service using svcs -l # svcs -l hg-serve fmri svc:/application/network/hg-serve:project-gate name hg-serve enabled false state disabled next_state none state_time Thu May 31 16:11:47 2012 logfile /var/svc/log/application-network-hg-serve:project-gate.log restarter svc:/system/svc/restarter:default contract_id 15749 manifest /var/svc/manifest/network/hg/hg-serve.xml dependency require_all/none svc:/milestone/network:default (online) And look at the interesting properties # svcprop hg-serve hg-serve/path astring /src/project-gate hg-serve/port astring 9998 ...stuff deleted.... Then simply enable the service and if every things gone right, you can point your browser at http://server:9998 and get a nice graphical log of project activity. # svcadm enable hg-serve # svcs -l hg-serve fmri svc:/application/network/hg-serve:project-gate name hg-serve enabled true state online next_state none state_time Thu May 31 16:18:11 2012 logfile /var/svc/log/application-network-hg-serve:project-gate.log restarter svc:/system/svc/restarter:default contract_id 15858 manifest /var/svc/manifest/network/hg/hg-serve.xml dependency require_all/none svc:/milestone/network:default (online) None of this is rocket science, but a bit fiddly. Hence I thought I'd blog it. It might just be you see this in google and it clicks with you more than one of the many other blogs or how tos about it. Plus I can always refer back to it myself in 3 weeks, when I want to add another project to the server, and I've forgotten how to do it.

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Android - Create a custom multi-line ListView bound to an ArrayList

- by Bill Osuch

The Android HelloListView tutorial shows how to bind a ListView to an array of string objects, but you'll probably outgrow that pretty quickly. This post will show you how to bind the ListView to an ArrayList of custom objects, as well as create a multi-line ListView. Let's say you have some sort of search functionality that returns a list of people, along with addresses and phone numbers. We're going to display that data in three formatted lines for each result, and make it clickable. First, create your new Android project, and create two layout files. Main.xml will probably already be created by default, so paste this in: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:layout_height="wrap_content" android:text="Custom ListView Contents" android:gravity="center_vertical|center_horizontal" android:layout_width="fill_parent" /> <ListView android:id="@+id/ListView01" android:layout_height="wrap_content" android:layout_width="fill_parent"/> </LinearLayout> Next, create a layout file called custom_row_view.xml. This layout will be the template for each individual row in the ListView. You can use pretty much any type of layout - Relative, Table, etc., but for this we'll just use Linear: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:id="@+id/name" android:textSize="14sp" android:textStyle="bold" android:textColor="#FFFF00" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <TextView android:id="@+id/cityState" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <TextView android:id="@+id/phone" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout> Now, add an object called SearchResults. Paste this code in: public class SearchResults { private String name = ""; private String cityState = ""; private String phone = ""; public void setName(String name) { this.name = name; } public String getName() { return name; } public void setCityState(String cityState) { this.cityState = cityState; } public String getCityState() { return cityState; } public void setPhone(String phone) { this.phone = phone; } public String getPhone() { return phone; } } This is the class that we'll be filling with our data, and loading into an ArrayList. Next, you'll need a custom adapter. This one just extends the BaseAdapter, but you could extend the ArrayAdapter if you prefer. public class MyCustomBaseAdapter extends BaseAdapter { private static ArrayList<SearchResults> searchArrayList; private LayoutInflater mInflater; public MyCustomBaseAdapter(Context context, ArrayList<SearchResults> results) { searchArrayList = results; mInflater = LayoutInflater.from(context); } public int getCount() { return searchArrayList.size(); } public Object getItem(int position) { return searchArrayList.get(position); } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder; if (convertView == null) { convertView = mInflater.inflate(R.layout.custom_row_view, null); holder = new ViewHolder(); holder.txtName = (TextView) convertView.findViewById(R.id.name); holder.txtCityState = (TextView) convertView.findViewById(R.id.cityState); holder.txtPhone = (TextView) convertView.findViewById(R.id.phone); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.txtName.setText(searchArrayList.get(position).getName()); holder.txtCityState.setText(searchArrayList.get(position).getCityState()); holder.txtPhone.setText(searchArrayList.get(position).getPhone()); return convertView; } static class ViewHolder { TextView txtName; TextView txtCityState; TextView txtPhone; } } (This is basically the same as the List14.java API demo) Finally, we'll wire it all up in the main class file: public class CustomListView extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ArrayList<SearchResults> searchResults = GetSearchResults(); final ListView lv1 = (ListView) findViewById(R.id.ListView01); lv1.setAdapter(new MyCustomBaseAdapter(this, searchResults)); lv1.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> a, View v, int position, long id) { Object o = lv1.getItemAtPosition(position); SearchResults fullObject = (SearchResults)o; Toast.makeText(ListViewBlogPost.this, "You have chosen: " + " " + fullObject.getName(), Toast.LENGTH_LONG).show(); } }); } private ArrayList<SearchResults> GetSearchResults(){ ArrayList<SearchResults> results = new ArrayList<SearchResults>(); SearchResults sr1 = new SearchResults(); sr1.setName("John Smith"); sr1.setCityState("Dallas, TX"); sr1.setPhone("214-555-1234"); results.add(sr1); sr1 = new SearchResults(); sr1.setName("Jane Doe"); sr1.setCityState("Atlanta, GA"); sr1.setPhone("469-555-2587"); results.add(sr1); sr1 = new SearchResults(); sr1.setName("Steve Young"); sr1.setCityState("Miami, FL"); sr1.setPhone("305-555-7895"); results.add(sr1); sr1 = new SearchResults(); sr1.setName("Fred Jones"); sr1.setCityState("Las Vegas, NV"); sr1.setPhone("612-555-8214"); results.add(sr1); return results; } } Notice that we first get an ArrayList of SearchResults objects (normally this would be from an external data source...), pass it to the custom adapter, then set up a click listener. The listener gets the item that was clicked, converts it back to a SearchResults object, and does whatever it needs to do. Fire it up in the emulator, and you should wind up with something like this:

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Microsoft Business Intelligence Seminar 2011

- by DavidWimbush

I was lucky enough to attend the maiden presentation of this at Microsoft Reading yesterday. It was pretty gripping stuff not only because of what was said but also because of what could only be hinted at. Here's what I took away from the day. (Disclaimer: I'm not a BI guru, just a reasonably experienced BI developer, so I may have misunderstood or misinterpreted a few things. Particularly when so much of the talk was about the vision and subtle hints of what is coming. Please comment if you think I've got anything wrong. I'm also not going to even try to cover Master Data Services as I struggled to imagine how you would actually use it.) I was a bit worried when I learned that the whole day was going to be presented by one guy but Rafal Lukawiecki is a very engaging speaker. He's going to be presenting this about 20 times around the world over the coming months. If you get a chance to hear him speak, I say go for it. No doubt some of the hints will become clearer as Denali gets closer to RTM. Firstly, things are definitely happening in the SQL Server Reporting and BI world. Traditionally IT would build a data warehouse, then cubes on top of that, and then publish them in a structured and controlled way. But, just as with many IT projects in general, by the time it's finished the business has moved on and the system no longer meets their requirements. This not sustainable and something more agile is needed but there has to be some control. Apparently we're going to be hearing the catchphrase 'Balancing agility with control' a lot. More users want more access to more data. Can they define what they want? Of course not, but they'll recognise it when they see it. It's estimated that only 28% of potential BI users have meaningful access to the data they need, so there is a real pent-up demand. The answer looks like: give them some self-service tools so they can experiment and see what works, and then IT can help to support the results. It's estimated that 32% of Excel users are comfortable with its analysis tools such as pivot tables. It's the power user's preferred tool. Why fight it? That's why PowerPivot is an Excel add-in and that's why they released a Data Mining add-in for it as well. It does appear that the strategy is going to be to use Reporting Services (in SharePoint mode), PowerPivot, and possibly something new (smiles and hints but no details) to create reports and explore data. Everything will be published and managed in SharePoint which gives users the ability to mash-up, share and socialise what they've found out. SharePoint also gives IT tools to understand what people are looking at and where to concentrate effort. If PowerPivot report X becomes widely used, it's time to check that it shows what they think it does and perhaps get it a bit more under central control. There was more SharePoint detail that went slightly over my head regarding where Excel Services and Excel Web Application fit in, the differences between them, and the suggestion that it is likely they will one day become one (but not in the immediate future). That basic pattern is set to be expanded upon by further exploiting Vertipaq (the columnar indexing engine that enables PowerPivot to store and process a lot of data fast and in a small memory footprint) to provide scalability 'from the desktop to the data centre', and some yet to be detailed advances in 'frictionless deployment' (part of which is about making the difference between local and the cloud pretty much irrelevant). Excel looks like becoming Microsoft's primary BI client. It already has: the ability to consume cubes strong visualisation tools slicers (which are part of Excel not PowerPivot) a data mining add-in PowerPivot A major hurdle for self-service BI is presenting the data in a consumable format. You can't just give users PowerPivot and a server with a copy of the OLTP database(s). Building cubes is labour intensive and doesn't always give the user what they need. This is where the BI Semantic Model (BISM) comes in. I gather it's a layer of metadata you define that can combine multiple data sources (and types of data source) into a clear 'interface' that users can work with. It comes with a new query language called DAX. SSAS cubes are unlikely to go away overnight because, with their pre-calculated results, they are still the most efficient way to work with really big data sets. A few other random titbits that came up: Reporting Services is going to get some good new stuff in Denali. Keep an eye on www.projectbotticelli.com for the slides. You can also view last year's seminar sessions which covered a lot of the same ground as far as the overall strategy is concerned. They plan to add more material as Denali's features are publicly exposed. Check out the PASS keynote address for a showing of Yahoo's SQL BI servers. Apparently they wheeled the rack out on stage still plugged in and running! Check out the Excel 2010 Data Mining Add-Ins. 32 bit only at present but 64 bit is on the way. There are lots of data sets, many of them free, at the Windows Azure Marketplace Data Market (where you can also get ESRI shape files). If you haven't already seen it, have a look at the Silverlight Pivot Viewer (http://weblogs.asp.net/scottgu/archive/2010/06/29/silverlight-pivotviewer-now-available.aspx). The Bing Maps Data Connector is worth a look if you're into spatial stuff (http://www.bing.com/community/site_blogs/b/maps/archive/2010/07/13/data-connector-sql-server-2008-spatial-amp-bing-maps.aspx).

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Modern/Metro Internet Explorer: What were they thinking???

- by Rick Strahl

As I installed Windows 8.1 last week I decided that I really should take a closer look at Internet Explorer in the Modern/Metro environment again. Right away I ran into two issues that are real head scratchers to me.Modern Split Windows don't resize Viewport but Zoom OutThis one falls in the "WTF, really?" department: It looks like Modern Internet Explorer's Modern doesn't resize the browser window as every other browser (including IE 11 on the desktop) does, but rather tries to adjust the zoom to the width of the browser. This means that if you use the Modern IE browser and you split the display between IE and another application, IE will be zoomed out, with text becoming much, much smaller, rather than resizing the browser viewport and adjusting the pixel width as you would when a browser window is typically resized.Here's what I'm talking about in a couple of pictures. First here's the full screen Internet Explorer version (this shot is resized down since it's full screen at 1080p, click to see the full image):This brings up the first issue which is: On the desktop who wants to browse a site full screen? Most sites aren't fully optimized for 1080p widescreen experience and frankly most content that wide just looks weird. Even in typical 10" resolutions of 1280 width it's weird to look at things this way. At least this issue can be worked around with @media queries and either constraining the view, or adding additional content to make use of the extra space. Still running a desktop browser full screen is not optimal on a desktop machine - ever.Regardless, this view, while oversized, is what I expect: Everything is rendered in the right ratios, with font-size and the responsive design styling properly respected.But now look what happens when you split the desktop windows and show half desktop and have modern IE (this screen shot is not resized but cropped - this is actual size content as you can see in the cropped Twitter window on the right half of the screen):What's happening here is that IE is zooming out of the content to make it fit into the smaller width, shrinking the content rather than resizing the viewport's pixel width. In effect it looks like the pixel width stays at 1080px and the viewport expands out height-wise in response resulting in some crazy long portrait view.There goes responsive design - out the window literally. If you've built your site using @media queries and fixed viewport sizes, Internet Explorer completely screws you in this split view. On my 1080p monitor, the site shown at a little under half width becomes completely unreadable as the fonts are too small and break up. As you go into split view and you resize the window handle the content of the browser gets smaller and smaller (and effectively longer and longer on the bottom) effectively throwing off any responsive layout to the point of un-readability even on a big display, let alone a small tablet screen.What could POSSIBLY be the benefit of this screwed up behavior? I checked around a bit trying different pages in this shrunk down view. Other than the Microsoft home page, every page I went to was nearly unreadable at a quarter width. The only page I found that worked 'normally' was the Microsoft home page which undoubtedly is optimized just for Internet Explorer specifically.Bottom Address Bar opaquely overlays ContentAnother problematic feature for me is the browser address bar on the bottom. Modern IE shows the status bar opaquely on the bottom, overlaying the content area of the Web Page - until you click on the page. Until you do though, the address bar overlays the bottom content solidly. And not just a little bit but by good sizable chunk.In the application from the screen shot above I have an application toolbar on the bottom and the IE Address bar completely hides that bottom toolbar when the page is first loaded, until the user clicks into the content at which point the address bar shrinks down to a fat border style bar with a … on it. Toolbars on the bottom are pretty common these days, especially for mobile optimized applications, so I'd say this is a common use case. But even if you don't have toolbars on the bottom maybe there's other fixed content on the bottom of the page that is vital to display. While other browsers often also show address bars and then later hide them, these other browsers tend to resize the viewport when the address bar status changes, so the content can respond to the size change. Not so with Modern IE. The address bar overlays content and stays visible until content is clicked. No resize notification or viewport height change is sent to the browser.So basically Internet Explorer is telling me: "Our toolbar is more important than your content!" - AND gives me no chance to re-act to that behavior. The result on this page/application is that the user sees no actionable operations until he or she clicks into the content area, which is terrible from a UI perspective as the user has no idea what options are available on initial load.It's doubly confounding in that IE is running in full screen mode and has an the entire height of the screen at its disposal - there's plenty of real estate available to not require this sort of hiding of content in the first place. Heck, even Windows Phone with its more constrained size doesn't hide content - in fact the address bar on Windows Phone 8 is always visible.What were they thinking?Every time I use anything in the Modern Metro interface in Windows 8/8.1 I get angry. I can pretty much ignore Metro/Modern for my everyday usage, but unfortunately with Internet Explorer in the modern shell I have to live with, because there will be users using it to access my sites. I think it's inexcusable by Microsoft to build such a crappy shell around the browser that impacts the actual usability of Web content. In both of the cases above I can only scratch my head at what could have possibly motivated anybody designing the UI for the browser to make these screwed up choices, that manipulate the content in a totally unmaintainable way.© Rick Strahl, West Wind Technologies, 2005-2013Posted in Windows HTML5 Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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ANTS Memory Profiler 7.0

- by James Michael Hare

I had always been a fan of ANTS products (Reflector is absolutely invaluable, and their performance profiler is great as well – very easy to use!), so I was curious to see what the ANTS Memory Profiler could show me. Background While a performance profiler will track how much time is typically spent in each unit of code, a memory profiler gives you much more detail on how and where your memory is being consumed and released in a program. As an example, I’d been working on a data access layer at work to call a market data web service. This web service would take a list of symbols to quote and would return back the quote data. To help consolidate the thousands of web requests per second we get and reduce load on the web services, we implemented a 5-second cache of quote data. Not quite long enough to where customers will typically notice a quote go “stale”, but just long enough to be able to collapse multiple quote requests for the same symbol in a short period of time. A 5-second cache may not sound like much, but it actually pays off by saving us roughly 42% of our web service calls, while still providing relatively up-to-date information. The question is whether or not the extra memory involved in maintaining the cache was worth it, so I decided to fire up the ANTS Memory Profiler and take a look at memory usage. First Impressions The main thing I’ve always loved about the ANTS tools is their ease of use. Pretty much everything is right there in front of you in a way that makes it easy for you to find what you need with little digging required. I’ve worked with other, older profilers before (that shall remain nameless other than to hint it was created by a very large chip maker) where it was a mind boggling experience to figure out how to do simple tasks. Not so with AMP. The opening dialog is very straightforward. You can choose from here whether to debug an executable, a web application (either in IIS or from VS’s web development server), windows services, etc. So I chose a .NET Executable and navigated to the build location of my test harness. Then began profiling. At this point while the application is running, you can see a chart of the memory as it ebbs and wanes with allocations and collections. At any given point in time, you can take snapshots (to compare states) zoom in, or choose to stop at any time. Snapshots Taking a snapshot also gives you a breakdown of the managed memory heaps for each generation so you get an idea how many objects are staying around for extended periods of time (as an object lives and survives collections, it gets promoted into higher generations where collection becomes less frequent). Generating a snapshot brings up an analysis view with very handy graphs that show your generation sizes. Almost all my memory is in Generation 1 in the managed memory component of the first graph, which is good news to me, because Gen 2 collections are much rarer. I once3 made the mistake once of caching data for 30 minutes and found it didn’t get collected very quick after I released my reference because it had been promoted to Gen 2 – doh! Analysis It looks like (from the second pie chart) that the majority of the allocations were in the string class. This also is expected for me because the majority of the memory allocated is in the web service responses, so it doesn’t seem the entities I’m adapting to (to prevent being too tightly coupled to the web service proxy classes, which can change easily out from under me) aren’t taking a significant portion of memory. I also appreciate that they have clear summary text in key places such as “No issues with large object heap fragmentation were detected”. For novice users, this type of summary information can be critical to getting them to use a tool and develop a good working knowledge of it. There is also a handy link at the bottom for “What to look for on the summary” which loads a web page of help on key points to look for. Clicking over to the session overview, it’s easy to compare the samples at each snapshot to see how your memory is growing, shrinking, or staying relatively the same. Looking at my snapshots, I’m pretty happy with the fact that memory allocation and heap size seems to be fairly stable and in control: Once again, you can check on the large object heap, generation one heap, and generation two heap across each snapshot to spot trends. Back on the analysis tab, we can go to the [Class List] button to get an idea what classes are making up the majority of our memory usage. As was little surprise to me, System.String was the clear majority of my allocations, though I found it surprising that the System.Reflection.RuntimeMehtodInfo came in second. I was curious about this, so I selected it and went into the [Instance Categorizer]. This view let me see where these instances to RuntimeMehtodInfo were coming from. So I scrolled back through the graph, and discovered that these were being held by the System.ServiceModel.ChannelFactoryRefCache and I was satisfied this was just an artifact of my WCF proxy. I also like that down at the bottom of the Instance Categorizer it gives you a series of filters and offers to guide you on which filter to use based on the problem you are trying to find. For example, if I suspected a memory leak, I might try to filter for survivors in growing classes. This means that for instances of a class that are growing in memory (more are being created than cleaned up), which ones are survivors (not collected) from garbage collection. This might allow me to drill down and find places where I’m holding onto references by mistake and not freeing them! Finally, if you want to really see all your instances and who is holding onto them (preventing collection), you can go to the “Instance Retention Graph” which creates a graph showing what references are being held in memory and who is holding onto them. Visual Studio Integration Of course, VS has its own profiler built in – and for a free bundled profiler it is quite capable – but AMP gives a much cleaner and easier-to-use experience, and when you install it you also get the option of letting it integrate directly into VS. So once you go back into VS after installation, you’ll notice an ANTS menu which lets you launch the ANTS profiler directly from Visual Studio. Clicking on one of these options fires up the project in the profiler immediately, allowing you to get right in. It doesn’t integrate with the Visual Studio windows themselves (like the VS profiler does), but still the plethora of information it provides and the clear and concise manner in which it presents it makes it well worth it. Summary If you like the ANTS series of tools, you shouldn’t be disappointed with the ANTS Memory Profiler. It was so easy to use that I was able to jump in with very little product knowledge and get the information I was looking it for. I’ve used other profilers before that came with 3-inch thick tomes that you had to read in order to get anywhere with the tool, and this one is not like that at all. It’s built for your everyday developer to get in and find their problems quickly, and I like that! Tweet Technorati Tags: Influencers,ANTS,Memory,Profiler

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SQL University: What and why of database refactoring

- by Mladen Prajdic

This is a post for a great idea called SQL University started by Jorge Segarra also famously known as SqlChicken on Twitter. It’s a collection of blog posts on different database related topics contributed by several smart people all over the world. So this week is mine and we’ll be talking about database testing and refactoring. In 3 posts we’ll cover: SQLU part 1 - What and why of database testing SQLU part 2 - What and why of database refactoring SQLU part 3 - Tools of the trade This is a second part of the series and in it we’ll take a look at what database refactoring is and why do it. Why refactor a database To know why refactor we first have to know what refactoring actually is. Code refactoring is a process where we change module internals in a way that does not change that module’s input/output behavior. For successful refactoring there is one crucial thing we absolutely must have: Tests. Automated unit tests are the only guarantee we have that we haven’t broken the input/output behavior before refactoring. If you haven’t go back ad read my post on the matter. Then start writing them. Next thing you need is a code module. Those are views, UDFs and stored procedures. By having direct table access we can kiss fast and sweet refactoring good bye. One more point to have a database abstraction layer. And no, ORM’s don’t fall into that category. But also know that refactoring is NOT adding new functionality to your code. Many have fallen into this trap. Don’t be one of them and resist the lure of the dark side. And it’s a strong lure. We developers in general love to add new stuff to our code, but hate fixing our own mistakes or changing existing code for no apparent reason. To be a good refactorer one needs discipline and focus. Now we know that refactoring is all about changing inner workings of existing code. This can be due to performance optimizations, changing internal code workflows or some other reason. This is a typical black box scenario to the outside world. If we upgrade the car engine it still has to drive on the road (preferably faster) and not fly (no matter how cool that would be). Also be aware that white box tests will break when we refactor. What to refactor in a database Refactoring databases doesn’t happen that often but when it does it can include a lot of stuff. Let us look at a few common cases. Adding or removing database schema objects Adding, removing or changing table columns in any way, adding constraints, keys, etc… All of these can be counted as internal changes not visible to the data consumer. But each of these carries a potential input/output behavior change. Dropping a column can result in views not working anymore or stored procedure logic crashing. Adding a unique constraint shows duplicated data that shouldn’t exist. Foreign keys break a truncate table command executed from an application that runs once a month. All these scenarios are very real and can happen. With the proper database abstraction layer fully covered with black box tests we can make sure something like that does not happen (hopefully at all). Changing physical structures Physical structures include heaps, indexes and partitions. We can pretty much add or remove those without changing the data returned by the database. But the performance can be affected. So here we use our performance tests. We do have them, right? Just by adding a single index we can achieve orders of magnitude performance improvement. Won’t that make users happy? But what if that index causes our write operations to crawl to a stop. again we have to test this. There are a lot of things to think about and have tests for. Without tests we can’t do successful refactoring! Fixing bad code We all have some bad code in our systems. We usually refer to that code as code smell as they violate good coding practices. Examples of such code smells are SQL injection, use of SELECT *, scalar UDFs or cursors, etc… Each of those is huge code smell and can result in major code changes. Take SELECT * from example. If we remove a column from a table the client using that SELECT * statement won’t have a clue about that until it runs. Then it will gracefully crash and burn. Not to mention the widely unknown SELECT * view refresh problem that Tomas LaRock (@SQLRockstar on Twitter) and Colin Stasiuk (@BenchmarkIT on Twitter) talk about in detail. Go read about it, it’s informative. Refactoring this includes replacing the * with column names and most likely change to application using the database. Breaking apart huge stored procedures Have you ever seen seen a stored procedure that was 2000 lines long? I have. It’s not pretty. It hurts the eyes and sucks the will to live the next 10 minutes. They are a maintenance nightmare and turn into things no one dares to touch. I’m willing to bet that 100% of time they don’t have a single test on them. Large stored procedures (and functions) are a clear sign that they contain business logic. General opinion on good database coding practices says that business logic has no business in the database. That’s the applications part. Refactoring such behemoths requires writing lots of edge case tests for the stored procedure input/output behavior and then start to refactor it. First we split the logic inside into smaller parts like new stored procedures and UDFs. Those then get called from the master stored procedure. Once we’ve successfully modularized the database code it’s best to transfer that logic into the applications consuming it. This only leaves the stored procedure with common data manipulation logic. Of course this isn’t always possible so having a plethora of performance and behavior unit tests is absolutely necessary to confirm we’ve actually improved the codebase in some way. Refactoring is not a popular chore amongst developers or managers. The former don’t like fixing old code, the latter can’t see the financial benefit. Remember how we talked about being lousy at estimating future costs in the previous post? But there comes a time when it must be done. Hopefully I’ve given you some ideas how to get started. In the last post of the series we’ll take a look at the tools to use and an example of testing and refactoring.

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DBCC CHECKDB on VVLDB and latches (Or: My Pain is Your Gain)

- by Argenis

Does your CHECKDB hurt, Argenis? There is a classic blog series by Paul Randal [blog|twitter] called “CHECKDB From Every Angle” which is pretty much mandatory reading for anybody who’s even remotely considering going for the MCM certification, or its replacement (the Microsoft Certified Solutions Master: Data Platform – makes my fingers hurt just from typing it). Of particular interest is the post “Consistency Options for a VLDB” – on it, Paul provides solid, timeless advice (I use the word “timeless” because it was written in 2007, and it all applies today!) on how to perform checks on very large databases. Well, here I was trying to figure out how to make CHECKDB run faster on a restored copy of one of our databases, which happens to exceed 7TB in size. The whole thing was taking several days on multiple systems, regardless of the storage used – SAS, SATA or even SSD…and I actually didn’t pay much attention to how long it was taking, or even bothered to look at the reasons why - as long as it was finishing okay and found no consistency errors. Yes – I know. That was a huge mistake, as corruption found in a database several days after taking place could only allow for further spread of the corruption – and potentially large data loss. In the last two weeks I increased my attention towards this problem, as we noticed that CHECKDB was taking EVEN LONGER on brand new all-flash storage in the SAN! I couldn’t really explain it, and were almost ready to blame the storage vendor. The vendor told us that they could initially see the server driving decent I/O – around 450Mb/sec, and then it would settle at a very slow rate of 10Mb/sec or so. “Hum”, I thought – “CHECKDB is just not pushing the I/O subsystem hard enough”. Perfmon confirmed the vendor’s observations. Dreaded @BlobEater What was CHECKDB doing all the time while doing so little I/O? Eating Blobs. It turns out that CHECKDB was taking an extremely long time on one of our frankentables, which happens to be have 35 billion rows (yup, with a b) and sucks up several terabytes of space in the database. We do have a project ongoing to purge/split/partition this table, so it’s just a matter of time before we deal with it. But the reality today is that CHECKDB is coming to a screeching halt in performance when dealing with this particular table. Checking sys.dm_os_waiting_tasks and sys.dm_os_latch_stats showed that LATCH_EX (DBCC_OBJECT_METADATA) was by far the top wait type. I remembered hearing recently about that wait from another post that Paul Randal made, but that was related to computed-column indexes, and in fact, Paul himself reminded me of his article via twitter. But alas, our pathologic table had no non-clustered indexes on computed columns. I knew that latches are used by the database engine to do internal synchronization – but how could I help speed this up? After all, this is stuff that doesn’t have a lot of knobs to tweak. (There’s a fantastic level 500 talk by Bob Ward from Microsoft CSS [blog|twitter] called “Inside SQL Server Latches” given at PASS 2010 – and you can check it out here. DISCLAIMER: I assume no responsibility for any brain melting that might ensue from watching Bob’s talk!) Failed Hypotheses Earlier on this week I flew down to Palo Alto, CA, to visit our Headquarters – and after having a great time with my Monkey peers, I was relaxing on the plane back to Seattle watching a great talk by SQL Server MVP and fellow MCM Maciej Pilecki [twitter] called “Masterclass: A Day in the Life of a Database Transaction” where he discusses many different topics related to transaction management inside SQL Server. Very good stuff, and when I got home it was a little late – that slow DBCC CHECKDB that I had been dealing with was way in the back of my head. As I was looking at the problem at hand earlier on this week, I thought “How about I set the database to read-only?” I remembered one of the things Maciej had (jokingly) said in his talk: “if you don’t want locking and blocking, set the database to read-only” (or something to that effect, pardon my loose memory). I immediately killed the CHECKDB which had been running painfully for days, and set the database to read-only mode. Then I ran DBCC CHECKDB against it. It started going really fast (even a bit faster than before), and then throttled down again to around 10Mb/sec. All sorts of expletives went through my head at the time. Sure enough, the same latching scenario was present. Oh well. I even spent some time trying to figure out if NUMA was hurting performance. Folks on Twitter made suggestions in this regard (thanks, Lonny! [twitter]) …Eureka? This past Friday I was still scratching my head about the whole thing; I was ready to start profiling with XPERF to see if I could figure out which part of the engine was to blame and then get Microsoft to look at the evidence. After getting a bunch of good news I’ll blog about separately, I sat down for a figurative smack down with CHECKDB before the weekend. And then the light bulb went on. A sparse column. I thought that I couldn’t possibly be experiencing the same scenario that Paul blogged about back in March showing extreme latching with non-clustered indexes on computed columns. Did I even have a non-clustered index on my sparse column? As it turns out, I did. I had one filtered non-clustered index – with the sparse column as the index key (and only column). To prove that this was the problem, I went and setup a test. Yup, that'll do it The repro is very simple for this issue: I tested it on the latest public builds of SQL Server 2008 R2 SP2 (CU6) and SQL Server 2012 SP1 (CU4). First, create a test database and a test table, which only needs to contain a sparse column: CREATE DATABASE SparseColTest; GO USE SparseColTest; GO CREATE TABLE testTable (testCol smalldatetime SPARSE NULL); GO INSERT INTO testTable (testCol) VALUES (NULL); GO 1000000 That’s 1 million rows, and even though you’re inserting NULLs, that’s going to take a while. In my laptop, it took 3 minutes and 31 seconds. Next, we run DBCC CHECKDB against the database: DBCC CHECKDB('SparseColTest') WITH NO_INFOMSGS, ALL_ERRORMSGS; This runs extremely fast, as least on my test rig – 198 milliseconds. Now let’s create a filtered non-clustered index on the sparse column: CREATE NONCLUSTERED INDEX [badBadIndex] ON testTable (testCol) WHERE testCol IS NOT NULL; With the index in place now, let’s run DBCC CHECKDB one more time: DBCC CHECKDB('SparseColTest') WITH NO_INFOMSGS, ALL_ERRORMSGS; In my test system this statement completed in 11433 milliseconds. 11.43 full seconds. Quite the jump from 198 milliseconds. I went ahead and dropped the filtered non-clustered indexes on the restored copy of our production database, and ran CHECKDB against that. We went down from 7+ days to 19 hours and 20 minutes. Cue the “Argenis is not impressed” meme, please, Mr. LaRock. My pain is your gain, folks. Go check to see if you have any of such indexes – they’re likely causing your consistency checks to run very, very slow. Happy CHECKDBing, -Argenis ps: I plan to file a Connect item for this issue – I consider it a pretty serious bug in the engine. After all, filtered indexes were invented BECAUSE of the sparse column feature – and it makes a lot of sense to use them together. Watch this space and my twitter timeline for a link.

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Day 3 - XNA: Hacking around with images

- by dapostolov

Yay! Today I'm going to get into some code! My mind has been on this all day! I find it amusing how I practice, daily, to be "in the moment" or "present" and the excitement and anticipation of this project seems to snatch it away from me frequently. WELL!!! (Shakes Excitedly) Let's do this =)! Let's code! For these next few days it is my intention to better understand image rendering using XNA; after said prototypes are complete I should (fingers crossed) be able to dive into my game code using the design document I hammered out the other night. On a personal note, I think the toughest thing right now is finding the time to do this project. Each night, after my little ones go to bed I can only really afford a couple hours of work on this project. However, I hope to utilise this time as best as I can because this is the first time in a while I've found a project that I've been passionate about. A friend recently asked me if I intend to go 3D or extend the game design. Yes. For now I'm keeping it simple. Lastly, just as a note, as I was doing some further research into image rendering this morning I came across some other XNA content and lessons learned. I believe this content could have probably been posted in the first couple of posts, however, I will share the new content as I learn it at the end of each day. Maybe I'll take some time later to fix the posts but for now Installation and Deployment - Lessons Learned I had installed the XNA studio (Day 1) and the site instructions were pretty easy to follow. However, I had a small difficulty with my development environment. You see, I run a virtual desktop development environment. Even though I was able to code and compile all the tutorials the game failed to run...because I lacked a 3D capable card; it was not detected on the virtual box... First Lesson: The XNA runtime needs to "see" the 3D card! No sweat, Il copied the files over to my parent box and executed the program. ERROR. Hmm... Second Lesson (which I should have probably known but I let the excitement get the better of me): you need the XNA runtime on the client PC to run the game, oh, and don't forget the .Net Runtime! Sprite, it ain't just a Soft Drink... With these prototypes I intend to understand and perform the following tasks. learn game development terminology how to place and position (rotate) a static image on the screen how to layer static images on the screen understand image scaling can we reuse images? understand how framerate is handled in XNA how to display text , basic shapes, and colors on the screen how to interact with an image (collision of user input?) how to animate an image and understand basic animation techniques how to detect colliding images or screen edges how to manipulate the image, lets say colors, stretching how to focus on a segment of an image...like only displaying a frame on a film reel what's the best way to manage images (compression, storage, location, prevent artwork theft, etc.) Well, let's start with this "prototype" task list for now...Today, let's get an image on the screen and maybe I can mark a few of the tasks as completed... C# Prototype1 New Visual Studio Project Select the XNA Game Studio 3.1 Project Type Select the Windows Game 3.1 Template Type Prototype1 in the Name textbox provided Press OK. At this point code has auto-magically been created. Feel free to press the F5 key to run your first XNA program. You should have a blue screen infront of you. Without getting into the nitty gritty right, the code that was generated basically creates some basic code to clear the window content with the lovely CornFlowerBlue color. Something to notice, when you move your mouse into the window...nothing. ooooo spoooky. Let's put an image on that screen! Step A - Get an Image into the solution Under "Content" in your Solution Explorer, right click and add a new folder and name it "Sprites". Copy a small image in there; I copied a "Royalty Free" wizard hat from a quick google search and named it wizards_hat.jpg (rightfully so!) Step B - Add the sprite and position fields Now, open/edit Game1.cs Locate the following line: SpriteBatch spriteBatch; Under this line type the following: SpriteBatch spriteBatch; // the line you are looking for... Texture2D sprite; Vector2 position; Step C - Load the image asset Locate the "Load Content" Method and duplicate the following: protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); // your image name goes here... sprite = Content.Load<Texture2D>("Sprites\\wizards_hat"); position = new Vector2(200, 100); base.LoadContent(); } Step D - Draw the image Locate the "Draw" Method and duplicate the following: protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(SpriteBlendMode.AlphaBlend); spriteBatch.Draw(sprite, position, Color.White); spriteBatch.End(); base.Draw(gameTime); } Step E - Compile and Run Engage! (F5) - Debug! Your image should now display on a cornflowerblue window about 200 pixels from the left and 100 pixels from the top. Awesome! =) Pretty cool how we only coded a few lines to display an image, but believe me, there is plenty going on behind the scenes. However, for now, I'm going to call it a night here. Blogging all this progress certainly takes time... However, tomorrow night I'm going to detail what we just did, plus start checking off points on that list! I'm wondering right now if I should add pictures / code to this post...let me know if you want them =) Best Regards, D.

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Moving from Tortoise to TFS

- by MarkPearl

The Past A few years ago my small software company made the jump from storing code on a shared folder to source code control. At the time we had evaluated a few of the options and settled on Tortoise SVN. The main motivation for going the SVN route was that we found a great plugin for Visual Studio that allowed us to avoid the command prompt for uploading changes (like I said we are windows programmers… command prompt bad!! ) and it was free. Up to now we have been pretty happy with SVN as it removed many of the worries that I had about how safe my code was on a shared folder and also gave us the opportunity to safely have several developers work on the same project at the same time. The only times when we have been unhappy has been when we have had SVN hell days – which pretty much occur when you are doing something out of the norm and suddenly SVN just won’t resolve conflicts or something along those lines. This happens once every 4 or 5 months and is not necessarily a problem caused directly by SVN – but a problem augmented by SVN. When you have SVN hell days you want to curse SVN! With that in mind I recently have been relooking at our source code control. I have explored using GIT and was very impressed by it and have also looked at TFS. From a source code control perspective I don’t want to get into a heated discussion on which one is better – but I do want to mention that I wear two hats in my organization – software developer & manager, and with the manager hat on I tend to sway the TFS route. So when I was given a coupon to test DiscountASP.Net Team Foundation Server Service for a year, I thought it was the perfect opportunity to try TFS in a distributed environment and also make the first step towards having an integrated development management system. Some of the things that appeal to me about DiscountASP’s offering are the following… Basic management / planning facilities like to do lists inside Visual Studio Daily backup of data on the server – we are developers, not IT managers and so the more of this I could outsource the better Distributed solution – all of us work remotely and so this was a big one as well. Registering and Setting Up with DiscountASP.NET The whole registration process was simple and intuitive. The web interface is not the most visually impressive one, but it is functional and a few seconds after I clicked the last submit button a email was sitting in my inbox giving me my control panel username and suggesting that I read the “Getting Started” article. The getting started article was easy to read and understand so no complaints there either. Next to set my dev environment to work. With a few references to the getting started article I had completed the whole setup process in a matter of minutes. Ten minutes after initiating the whole thing I was logged into VS2010 and creating my first TFS project. With the service that I signed up for, I have access for 5 users – which is sufficient for my internal needs. So from what I can tell, to set the rest of us up on the system I just need to supply them with their user credentials and url. My Concerns Resolved 1) Security So, a few concerns I had about the service. First and foremost – is it secure? I would hate for someone to get access to our code and the whole idea of putting it up on the internet is a concern for me. Turning to the Knowledge Base on the DiscountASP website this is one of the first question I can see answered. According to them it is secure. I have extracted their comment below regarding this. Our TFS hosting service is secure. We only accept HTTPS connections ensuring that any client-server data transmission is encrypted. At the network level, all of our systems are protected by multiple Juniper firewalls, Tipping Point's Intrusion Detection System (see Tipping Point's case study of our use here), and we also employ DDoS mitigation to add extra layers of security. Additionally, physical access to the servers is tightly restricted. Please see the security section of this Knowledge Base article for further details. 2) Web Portal Access The other big concern I have is regarding web portal access. In the ideal world I would like to be able to give my end users access to a web portal for reporting bugs etc. When I initially read through the FAQ of the site it mentioned that there was web portal access – but from what I can see this is just for “users”. Since I am limited to 5 users for the account, it would not be practical to set up external users that we could get feedback from on bugs etc. I would be interested if this is possible – and if so if someone could post it in the comments it would be much appreciated. If this isn’t possible, it is a slight let down as we rely heavily on end user feedback to get feedback and it would have been ideal to have gotten this within the service. Other than those two items, I didn’t have any real concerns that were unresolved. So where do I go from here? So time passed by from the initial writing of this post and as work whirred in and out of my inbox I have still not had a proper opportunity to give the service a test run. Recently though things have began to slow down and then surprise surprise I had another SVN Hell day. With that experience I had a new found resolve to get our team on TFS and so today we are going to start to use the service as a team. I am hoping that I do not have TFS hell days – but if I do, I will be sure to write about them. In short - the verdict is still out on whether this service is going to be invaluable to my business or whether it will create more headaches than it is worth BUT I am hopping it will be an invaluable service. I will only really be able to determine that in a few months… till then!

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JSP Precompilation for ADF Applications

- by Duncan Mills

A question that comes up from time to time, particularly in relation to build automation, is how to best pre-compile the .jspx and .jsff files in an ADF application. Thus ensuring that the app is ready to run as soon as it's installed into WebLogic. In the normal run of things, the first poor soul to hit a page pays the price and has to wait a little whilst the JSP is compiled into a servlet. Everyone else subsequently gets a free lunch. So it's a reasonable thing to want to do... Let Me List the Ways So forth to Google (other search engines are available)... which lead me to a fairly old article on WLDJ - Removing Performance Bottlenecks Through JSP Precompilation. Technololgy wise, it's somewhat out of date, but the one good point that it made is that it's really not very useful to try and use the precompile option in the weblogic.xml file. That's a really good observation - particularly if you're trying to integrate a pre-compile step into a Hudson Continuous Integration process. That same article mentioned an alternative approach for programmatic pre-compilation using weblogic.jspc. This seemed like a much more useful approach for a CI environment. However, weblogic.jspc is now obsoleted by weblogic.appc so we'll use that instead. Thanks to Steve for the pointer there. And So To APPC APPC has documentation - always a great place to start, and supports usage both from Ant via the wlappc task and from the command line using the weblogic.appc command. In my testing I took the latter approach. Usage, as the documentation will show you, is superficially pretty simple. The nice thing here, is that you can pass an existing EAR file (generated of course using OJDeploy) and that EAR will be updated in place with the freshly compiled servlet classes created from the JSPs. Appc takes care of all the unpacking, compiling and re-packing of the EAR for you. Neat. So we're done right...? Not quite. The Devil is in the Detail OK so I'm being overly dramatic but it's not all plain sailing, so here's a short guide to using weblogic.appc to compile a simple ADF application without pain. Information You'll Need The following is based on the assumption that you have a stand-alone WLS install with the Application Development Runtime installed and a suitable ADF enabled domain created. This could of course all be run off of a JDeveloper install as well 1. Your Weblogic home directory. Everything you need is relative to this so make a note. In my case it's c:\builds\wls_ps4. 2. Next deploy your EAR as normal and have a peek inside it using your favourite zip management tool. First of all look at the weblogic-application.xml inside the EAR /META-INF directory. Have a look for any library references. Something like this: <library-ref> <library-name>adf.oracle.domain</library-name> </library-ref> Make a note of the library ref (adf.oracle.domain in this case) , you'll need that in a second. 3. Next open the nested WAR file within the EAR and then have a peek inside the weblogic.xml file in the /WEB-INF directory. Again make a note of the library references. 4. Now start the WebLogic as per normal and run the WebLogic console app (e.g. http://localhost:7001/console). In the Domain Structure navigator, select Deployments. 5. For each of the libraries you noted down drill into the library definition and make a note of the .war, .ear or .jar that defines the library. For example, in my case adf.oracle.domain maps to "C:\ builds\ WLS_PS4\ oracle_common\ modules\ oracle. adf. model_11. 1. 1\ adf. oracle. domain. ear". Note the extra spaces that are salted throughout this string as it is displayed in the console - just to make it annoying, you'll have to strip these out. 6. Finally you'll need the location of the adfsharebean.jar. We need to pass this on the classpath for APPC so that the ADFConfigLifeCycleCallBack listener can be found. In a more complex app of your own you may need additional classpath entries as well. Now we're ready to go, and it's a simple matter of applying the information we have gathered into the relevant command line arguments for the utility A Simple CMD File to Run APPC Here's the stub .cmd file I'm using on Windows to run this. @echo offREM Stub weblogic.appc Runner setlocal set WLS_HOME=C:\builds\WLS_PS4 set ADF_LIB_ROOT=%WLS_HOME%\oracle_common\modulesset COMMON_LIB_ROOT=%WLS_HOME%\wlserver_10.3\common\deployable-libraries set ADF_WEBAPP=%ADF_LIB_ROOT%\oracle.adf.view_11.1.1\adf.oracle.domain.webapp.war set ADF_DOMAIN=%ADF_LIB_ROOT%\oracle.adf.model_11.1.1\adf.oracle.domain.ear set JSTL=%COMMON_LIB_ROOT%\jstl-1.2.war set JSF=%COMMON_LIB_ROOT%\jsf-1.2.war set ADF_SHARE=%ADF_LIB_ROOT%\oracle.adf.share_11.1.1\adfsharembean.jar REM Set up the WebLogic Environment so appc can be found call %WLS_HOME%\wlserver_10.3\server\bin\setWLSEnv.cmd CLS REM Now compile away!java weblogic.appc -verbose -library %ADF_WEBAPP%,%ADF_DOMAIN%,%JSTL%,%JSF% -classpath %ADF_SHARE% %1 endlocal Running the above on a target ADF .ear file will zip through and create all of the relevant compiled classes inside your nested .war file in the \WEB-INF\classes\jsp_servlet\ directory (but don't take my word for it, run it and take a look!) And So... In the immortal words of the Pet Shop Boys, Was It Worth It? Well, here's where you'll have to do your own testing. In my case here, with a simple ADF application, pre-compilation shaved an non-scientific "3 Elephants" off of the initial page load time for the first access of each page. That's a pretty significant payback for such a simple step to add into your CI process, so why not give it a go.

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When is a Seek not a Seek?

- by Paul White

The following script creates a single-column clustered table containing the integers from 1 to 1,000 inclusive. IF OBJECT_ID(N'tempdb..#Test', N'U') IS NOT NULL DROP TABLE #Test ; GO CREATE TABLE #Test ( id INTEGER PRIMARY KEY CLUSTERED ); ; INSERT #Test (id) SELECT V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 1000 ; Let’s say we need to find the rows with values from 100 to 170, excluding any values that divide exactly by 10. One way to write that query would be: SELECT T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; That query produces a pretty efficient-looking query plan: Knowing that the source column is defined as an INTEGER, we could also express the query this way: SELECT T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; We get a similar-looking plan: If you look closely, you might notice that the line connecting the two icons is a little thinner than before. The first query is estimated to produce 61.9167 rows – very close to the 63 rows we know the query will return. The second query presents a tougher challenge for SQL Server because it doesn’t know how to predict the selectivity of the modulo expression (T.id % 10 > 0). Without that last line, the second query is estimated to produce 68.1667 rows – a slight overestimate. Adding the opaque modulo expression results in SQL Server guessing at the selectivity. As you may know, the selectivity guess for a greater-than operation is 30%, so the final estimate is 30% of 68.1667, which comes to 20.45 rows. The second difference is that the Clustered Index Seek is costed at 99% of the estimated total for the statement. For some reason, the final SELECT operator is assigned a small cost of 0.0000484 units; I have absolutely no idea why this is so, or what it models. Nevertheless, we can compare the total cost for both queries: the first one comes in at 0.0033501 units, and the second at 0.0034054. The important point is that the second query is costed very slightly higher than the first, even though it is expected to produce many fewer rows (20.45 versus 61.9167). If you run the two queries, they produce exactly the same results, and both complete so quickly that it is impossible to measure CPU usage for a single execution. We can, however, compare the I/O statistics for a single run by running the queries with STATISTICS IO ON: Table '#Test'. Scan count 63, logical reads 126, physical reads 0. Table '#Test'. Scan count 01, logical reads 002, physical reads 0. The query with the IN list uses 126 logical reads (and has a ‘scan count’ of 63), while the second query form completes with just 2 logical reads (and a ‘scan count’ of 1). It is no coincidence that 126 = 63 * 2, by the way. It is almost as if the first query is doing 63 seeks, compared to one for the second query. In fact, that is exactly what it is doing. There is no indication of this in the graphical plan, or the tool-tip that appears when you hover your mouse over the Clustered Index Seek icon. To see the 63 seek operations, you have click on the Seek icon and look in the Properties window (press F4, or right-click and choose from the menu): The Seek Predicates list shows a total of 63 seek operations – one for each of the values from the IN list contained in the first query. I have expanded the first seek node to show the details; it is seeking down the clustered index to find the entry with the value 101. Each of the other 62 nodes expands similarly, and the same information is contained (even more verbosely) in the XML form of the plan. Each of the 63 seek operations starts at the root of the clustered index B-tree and navigates down to the leaf page that contains the sought key value. Our table is just large enough to need a separate root page, so each seek incurs 2 logical reads (one for the root, and one for the leaf). We can see the index depth using the INDEXPROPERTY function, or by using the a DMV: SELECT S.index_type_desc, S.index_depth FROM sys.dm_db_index_physical_stats ( DB_ID(N'tempdb'), OBJECT_ID(N'tempdb..#Test', N'U'), 1, 1, DEFAULT ) AS S ; Let’s look now at the Properties window when the Clustered Index Seek from the second query is selected: There is just one seek operation, which starts at the root of the index and navigates the B-tree looking for the first key that matches the Start range condition (id >= 101). It then continues to read records at the leaf level of the index (following links between leaf-level pages if necessary) until it finds a row that does not meet the End range condition (id <= 169). Every row that meets the seek range condition is also tested against the Residual Predicate highlighted above (id % 10 > 0), and is only returned if it matches that as well. You will not be surprised that the single seek (with a range scan and residual predicate) is much more efficient than 63 singleton seeks. It is not 63 times more efficient (as the logical reads comparison would suggest), but it is around three times faster. Let’s run both query forms 10,000 times and measure the elapsed time: DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON; SET STATISTICS XML OFF; ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id IN ( 101,102,103,104,105,106,107,108,109, 111,112,113,114,115,116,117,118,119, 121,122,123,124,125,126,127,128,129, 131,132,133,134,135,136,137,138,139, 141,142,143,144,145,146,147,148,149, 151,152,153,154,155,156,157,158,159, 161,162,163,164,165,166,167,168,169 ) ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; GO DECLARE @i INTEGER, @n INTEGER = 10000, @s DATETIME = GETDATE() ; SET NOCOUNT ON ; WHILE @n > 0 BEGIN SELECT @i = T.id FROM #Test AS T WHERE T.id >= 101 AND T.id <= 169 AND T.id % 10 > 0 ; SET @n -= 1; END ; PRINT DATEDIFF(MILLISECOND, @s, GETDATE()) ; On my laptop, running SQL Server 2008 build 4272 (SP2 CU2), the IN form of the query takes around 830ms and the range query about 300ms. The main point of this post is not performance, however – it is meant as an introduction to the next few parts in this mini-series that will continue to explore scans and seeks in detail. When is a seek not a seek? When it is 63 seeks © Paul White 2011 email: [email protected] twitter: @SQL_kiwi

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5 Ways Android Still Disappoints (Me)

- by TStewartDev

Let me make this clear: I'm annoyed with Apple. I don't like their current policies and I don't like where Steve Jobs is taking the company. In general, I don't like it when any one company gets too much control in a market. When that happens, the leading company dictates the game and as consumers, our options all but disappear. That said, I'm still going to buy a new iPhone next week. My Apple-hating friends seem to desperately want me to go Android instead, but frankly, it's not good enough for me, and here are the reasons why. The Modern WinMo One of the reasons that Microsoft has identified for Windows Mobile's rapid decline is the breadth of hardware. They exercised little control over manufacturer's implementations. In theory, that sounds great. We as consumers have lots of choice. In practice, though, it meant among other things that updates to the devices were left up to the manufacturers. As a result, that rarely happened. (I'm still bitter at Toshiba for leaving me hanging back in 2002.) And now, Google is doing the same thing with Android. Case in point: my wife has a Motorola Backflip that we bought in April. It was released in March. Motorola says it will get Android 2.1 "sometime in Q3". Great. Meanwhile, I pull down the latest version of iPhone OS (now iOS) and install it the same day it's released. You may say that I can't judge Android by one lazy manufacturer. Yup, I sure can. With Apple, my original iPhone has been supported perfectly for 3 years. With Android, I will have to wait for upgrades after Google releases them, possibly indefinitely. Not cool. AT&T We signed a new contract with AT&T in April to get my wife's phone. I've had a reasonable experience with them. I don't imagine my experience with Verizon would be any better, and I'm relatively confident that Sprint doesn't have the coverage it takes to work well for us. The fact is, AT&T, for whatever reason, doesn't have jack for Android phones. May not be Android's fault, but it's still a shortcoming that prevents me from having it just like the iPhone's exclusivity keeps some folks on other networks from having it. Innovation? What Innovation? Android has a nice dashboard and a great notification system and… nothing else original. I keep reading about how disappointing the iPhone is nowadays. "It has no innovation," people say. Who does? Android has modeled its behavior after the iPhone. That's fine, but if all you've got is a similar product and I'm invested both skill-wise and app-wise in my current platform, why should I change? Microsoft's new Windows Phone 7 looks somewhat innovative, and I'm pretty excited to see what they'll bring to the table, but that's another six months away, at least. I've got a 3 year old phone that has some annoying issues now (thanks to recent encounters with water). I need a new phone now. Is This Going to Work? There's no shortage of criticism of Apple over its App Store policies, and I've vented my own anger about it. However, I will give them credit: their screening of apps has done a great job of weeding out the crap and gives an excellent indication that the app will work on my device. How about Android? Nope. It might work on your phone. Maybe. You'll have to try it to see. Get burned by it? Well, write a nasty review to try to keep others from making the mistake you did. If you don't mind doing that stuff, then Android is the platform for you. Personally, I'd rather have a receptionist screening out the telemarketing and survey calls than hang up on them myself, but that's your call. Slow, Slowing, Slower All this yapping about multitasking. This is an area I've been on Apple's side from the beginning. Sorry folks, but this is the number one reason I hated Windows Mobile: the longer you use it, the slower it gets because it doesn't kill apps. I'm with Steve Jobs on this one: if you see a task manager, we're doing it wrong. I don't want to have to manually kill apps. I hate doing that on Windows let alone on a mobile device. To me, priority one should be keeping the device speedy. Waiting for your device to respond is unacceptable. Bonus! Taken from iPhone Letdown? 8 Things Apple Didn't Announce, here are my responses: 4G Yeah, let me know if your area actually has it. I live in Lincoln, Nebraska. No carrier is going to have 4G here for at least 3 years. Meanwhile, you still get to pay for it. Yay! Cloud iTunes/OTA Sync You got me here. Of course, whether or not your Android device will be able to do it is always a good question. 3G Video Chat You got me here, too. I'm sure you spent countless hours in front of your phone with video chat. Also, I can't wait for the "No Video Chat While Driving" laws. Mobile Hotspot This is a neat feature, but as the author points out, it's left up to the carrier whether to implement it or not. Pretty sure any Android phones that come to AT&T won't have this enabled in the foreseeable future. Is Verizon even allowing this? I just figured Sprint was because they're failing so hard at keeping customers. Free MobileMe I use Google's services with my iPhone. The only people I know who use MobileMe are Apple fanboys and fangirls. If you choose to pay for a service that you can get for free, that's your decision, not Apple's. Voice Input Voice input has been available on phones (even "dumb" phones) for years now. iPhone does have the ability, though limited. Why don't I hear people telling their phones what to do? Maybe because it's still easier to use your fingers than talk to it. Get back to me when this becomes an important feature. Free Navigation Maybe this will be a bigger deal to me now that I'm getting a phone with GPS, but when using my buddy's 3gs, Google maps has worked just fine. Maybe I just don't trust turn-by-turn navigation enough to want it. Dashboard The only legitimate complaint on this list, to me. iPhone's home screen is pathetic, doubly so for the iPad. What a waste of perfectly usable space. I also want to add notifications to this list. Android's notification panel is far superior to the iPhone's. I don't want to hunt all over my screen to find little red dots. Put 'em in one place, Apple.

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Sorting a Linked List [closed]

- by Mohit Sehgal

I want to sort a linked list. Here Node is class representing a node in a Linked List I have written a code to bubble sort a linked list. Program does not finishes execution. Kindly point out the mistakes. class Node { public: int data; public: Node *next; Node() { data=0;next=0; } Node(int d) { data=d; } void setData(int d) { data=d; } void print() { cout<<data<<endl; } bool operator==(Node n) { return this->data==n.data; } bool operator >(Node d) { if((this->data) > (d.data)) return true; return false; } }; class LList { public: int noOfNodes; Node *start;/*Header Node*/ LList() { start=new Node; noOfNodes=0;start=0; } void addAtFront(Node* n) { n->next=(start); start=n; noOfNodes++; } void addAtLast(Node* n) { Node *cur=(start); n->next=NULL; if(start==NULL) { start=n; noOfNodes++; return; } while(cur->next!=NULL) { cur=cur->next; } cur->next=n; noOfNodes++; } void addAtPos(Node *n,int pos) { if(pos==1) { addAtFront(n);return; } Node *cur=(start); Node *prev=NULL; int curPos=0; n->next=NULL; while(cur!=NULL) { curPos++; if(pos==curPos+1) { prev=cur; } if(pos==curPos) { n->next=cur; prev->next=n; break; } cur=cur->next; } noOfNodes++; } void removeFirst() { Node *del=start; start=start->next; delete del; noOfNodes--; return; } void removeLast() { Node *cur=start,*prev=NULL; while(cur->next!=NULL) { prev=cur; cur=cur->next; } prev->next=NULL; Node *del=cur->next; delete del; noOfNodes--; return; } void removeNodeAt(int pos) { if(pos<1) return; if(pos==1) { removeFirst();return;} int curPos=1; Node* cur=start->next; Node* prev=start; Node* del=NULL; while(curPos<pos&&cur!=NULL) { curPos++; if(curPos==pos) { del=cur; prev->next=cur->next; cur->next=NULL; delete del; noOfNodes--; break; } prev=prev->next; cur=cur->next; } } void removeNode(Node *d) { Node *cur=start; if(*d==*cur) { removeFirst();return; } cur=start->next; Node *prev=start,*del=NULL; while(cur!=NULL) { if(*cur==*d) { del=cur; prev->next=cur->next; delete del; noOfNodes--; break; } prev=prev->next; cur=cur->next; } } int getPosition(Node data) { int pos=0; Node *cur=(start); while(cur!=NULL) { pos++; if(*cur==data) { return pos; } cur=cur->next; } return -1;//not found } Node getNode(int pos) { if(pos<1) return -1;// not a valid position else if(pos>noOfNodes) return -1; // not a valid position Node *cur=(start); int curPos=0; while(cur!=NULL) { if(++curPos==pos) return *cur; cur=cur->next; } } void reverseList()//reverse the list { Node* cur=start->next; Node* d=NULL; Node* prev=start; while(cur!=NULL) { d=cur->next; cur->next=start; start=cur; prev->next=d; cur=d; } } void sortBubble() { Node *i=start,*j=start,*prev=NULL,*temp=NULL,*after=NULL; int count=noOfNodes-1;int icount=0; while(i->next!=NULL) { j=start; after=j->next; icount=0; while(++icount!=count) { if((*j)>(*after)) { temp=after->next; after->next=j; prev->next=j->next; j->next=temp; prev=after; after=j->next; } else{ prev=j; j=after; after=after->next; } } i=i->next; count--; } } void traverse() { Node *cur=(start); int c=0; while(cur!=NULL) { // cout<<"start"<<start; c++; cur->print(); cur=cur->next; } noOfNodes=c; } ~LList() { delete start; } }; int main() { int n; cin>>n; int d; LList list; Node *node; Node *temp=new Node(2123); for(int i=0;i<n;i++) { cin>>d; node=new Node(d); list.addAtLast(node); } list.addAtPos(temp,1); cout<<"traverse\n"; list.traverse(); temp=new Node(12); list.removeNode(temp); cout<<"12 removed"; list.traverse(); list.reverseList(); cout<<"\nreversed\n"; list.traverse(); cout<<"bubble sort\n"; list.sortBubble(); list.traverse(); getch(); delete node; return 0; }

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MapReduce in DryadLINQ and PLINQ

- by JoshReuben

MapReduce See http://en.wikipedia.org/wiki/Mapreduce The MapReduce pattern aims to handle large-scale computations across a cluster of servers, often involving massive amounts of data. "The computation takes a set of input key/value pairs, and produces a set of output key/value pairs. The developer expresses the computation as two Func delegates: Map and Reduce. Map - takes a single input pair and produces a set of intermediate key/value pairs. The MapReduce function groups results by key and passes them to the Reduce function. Reduce - accepts an intermediate key I and a set of values for that key. It merges together these values to form a possibly smaller set of values. Typically just zero or one output value is produced per Reduce invocation. The intermediate values are supplied to the user's Reduce function via an iterator." the canonical MapReduce example: counting word frequency in a text file. MapReduce using DryadLINQ see http://research.microsoft.com/en-us/projects/dryadlinq/ and http://connect.microsoft.com/Dryad DryadLINQ provides a simple and straightforward way to implement MapReduce operations. This The implementation has two primary components: A Pair structure, which serves as a data container. A MapReduce method, which counts word frequency and returns the top five words. The Pair Structure - Pair has two properties: Word is a string that holds a word or key. Count is an int that holds the word count. The structure also overrides ToString to simplify printing the results. The following example shows the Pair implementation. public struct Pair { private string word; private int count; public Pair(string w, int c) { word = w; count = c; } public int Count { get { return count; } } public string Word { get { return word; } } public override string ToString() { return word + ":" + count.ToString(); } } The MapReduce function that gets the results. the input data could be partitioned and distributed across the cluster. 1. Creates a DryadTable<LineRecord> object, inputTable, to represent the lines of input text. For partitioned data, use GetPartitionedTable<T> instead of GetTable<T> and pass the method a metadata file. 2. Applies the SelectMany operator to inputTable to transform the collection of lines into collection of words. The String.Split method converts the line into a collection of words. SelectMany concatenates the collections created by Split into a single IQueryable<string> collection named words, which represents all the words in the file. 3. Performs the Map part of the operation by applying GroupBy to the words object. The GroupBy operation groups elements with the same key, which is defined by the selector delegate. This creates a higher order collection, whose elements are groups. In this case, the delegate is an identity function, so the key is the word itself and the operation creates a groups collection that consists of groups of identical words. 4. Performs the Reduce part of the operation by applying Select to groups. This operation reduces the groups of words from Step 3 to an IQueryable<Pair> collection named counts that represents the unique words in the file and how many instances there are of each word. Each key value in groups represents a unique word, so Select creates one Pair object for each unique word. IGrouping.Count returns the number of items in the group, so each Pair object's Count member is set to the number of instances of the word. 5. Applies OrderByDescending to counts. This operation sorts the input collection in descending order of frequency and creates an ordered collection named ordered. 6. Applies Take to ordered to create an IQueryable<Pair> collection named top, which contains the 100 most common words in the input file, and their frequency. Test then uses the Pair object's ToString implementation to print the top one hundred words, and their frequency. public static IQueryable<Pair> MapReduce( string directory, string fileName, int k) { DryadDataContext ddc = new DryadDataContext("file://" + directory); DryadTable<LineRecord> inputTable = ddc.GetTable<LineRecord>(fileName); IQueryable<string> words = inputTable.SelectMany(x => x.line.Split(' ')); IQueryable<IGrouping<string, string>> groups = words.GroupBy(x => x); IQueryable<Pair> counts = groups.Select(x => new Pair(x.Key, x.Count())); IQueryable<Pair> ordered = counts.OrderByDescending(x => x.Count); IQueryable<Pair> top = ordered.Take(k); return top; } To Test: IQueryable<Pair> results = MapReduce(@"c:\DryadData\input", "TestFile.txt", 100); foreach (Pair words in results) Debug.Print(words.ToString()); Note: DryadLINQ applications can use a more compact way to represent the query: return inputTable .SelectMany(x => x.line.Split(' ')) .GroupBy(x => x) .Select(x => new Pair(x.Key, x.Count())) .OrderByDescending(x => x.Count) .Take(k); MapReduce using PLINQ The pattern is relevant even for a single multi-core machine, however. We can write our own PLINQ MapReduce in a few lines. the Map function takes a single input value and returns a set of mapped values àLINQ's SelectMany operator. These are then grouped according to an intermediate key à LINQ GroupBy operator. The Reduce function takes each intermediate key and a set of values for that key, and produces any number of outputs per key à LINQ SelectMany again. We can put all of this together to implement MapReduce in PLINQ that returns a ParallelQuery<T> public static ParallelQuery<TResult> MapReduce<TSource, TMapped, TKey, TResult>( this ParallelQuery<TSource> source, Func<TSource, IEnumerable<TMapped>> map, Func<TMapped, TKey> keySelector, Func<IGrouping<TKey, TMapped>, IEnumerable<TResult>> reduce) { return source .SelectMany(map) .GroupBy(keySelector) .SelectMany(reduce); } the map function takes in an input document and outputs all of the words in that document. The grouping phase groups all of the identical words together, such that the reduce phase can then count the words in each group and output a word/count pair for each grouping: var files = Directory.EnumerateFiles(dirPath, "*.txt").AsParallel(); var counts = files.MapReduce( path => File.ReadLines(path).SelectMany(line => line.Split(delimiters)), word => word, group => new[] { new KeyValuePair<string, int>(group.Key, group.Count()) });

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12c - SQL Text Expansion

- by noreply(at)blogger.com (Thomas Kyte)

Here is another small but very useful new feature in Oracle Database 12c - SQL Text Expansion. It will come in handy in two cases:You are asked to tune what looks like a simple query - maybe a two table join with simple predicates. But it turns out the two tables are each views of views of views and so on... In other words, you've been asked to 'tune' a 15 page query, not a two liner.You are asked to take a look at a query against tables with VPD (virtual private database) policies. In order words, you have no idea what you are trying to 'tune'.A new function, EXPAND_SQL_TEXT, in the DBMS_UTILITY package makes seeing what the "real" SQL is quite easy. For example - take the common view ALL_USERS - we can now:ops$tkyte%ORA12CR1> variable x clobops$tkyte%ORA12CR1> begin 2 dbms_utility.expand_sql_text 3 ( input_sql_text => 'select * from all_users', 4 output_sql_text => :x ); 5 end; 6 /PL/SQL procedure successfully completed.ops$tkyte%ORA12CR1> print xX--------------------------------------------------------------------------------SELECT "A1"."USERNAME" "USERNAME","A1"."USER_ID" "USER_ID","A1"."CREATED" "CREATED","A1"."COMMON" "COMMON" FROM (SELECT "A4"."NAME" "USERNAME","A4"."USER#" "USER_ID","A4"."CTIME" "CREATED",DECODE(BITAND("A4"."SPARE1",128),128,'YES','NO') "COMMON" FROM "SYS"."USER$" "A4","SYS"."TS$" "A3","SYS"."TS$" "A2" WHERE "A4"."DATATS#"="A3"."TS#" AND "A4"."TEMPTS#"="A2"."TS#" AND "A4"."TYPE#"=1) "A1"Now it is easy to see what query is really being executed at runtime - regardless of how many views of views you might have. You can see the expanded text - and that will probably lead you to the conclusion that maybe that 27 table join to 25 tables you don't even care about might better be written as a two table join.Further, if you've ever tried to figure out what a VPD policy might be doing to your SQL, you know it was hard to do at best. Christian Antognini wrote up a way to sort of see it - but you never get to see the entire SQL statement: http://www.antognini.ch/2010/02/tracing-vpd-predicates/. But now with this function - it becomes rather trivial to see the expanded SQL - after the VPD has been applied. We can see this by setting up a small table with a VPD policy ops$tkyte%ORA12CR1> create table my_table 2 ( data varchar2(30), 3 OWNER varchar2(30) default USER 4 ) 5 /Table created.ops$tkyte%ORA12CR1> create or replace 2 function my_security_function( p_schema in varchar2, 3 p_object in varchar2 ) 4 return varchar2 5 as 6 begin 7 return 'owner = USER'; 8 end; 9 /Function created.ops$tkyte%ORA12CR1> begin 2 dbms_rls.add_policy 3 ( object_schema => user, 4 object_name => 'MY_TABLE', 5 policy_name => 'MY_POLICY', 6 function_schema => user, 7 policy_function => 'My_Security_Function', 8 statement_types => 'select, insert, update, delete' , 9 update_check => TRUE ); 10 end; 11 /PL/SQL procedure successfully completed.And then expanding a query against it:ops$tkyte%ORA12CR1> begin 2 dbms_utility.expand_sql_text 3 ( input_sql_text => 'select * from my_table', 4 output_sql_text => :x ); 5 end; 6 /PL/SQL procedure successfully completed.ops$tkyte%ORA12CR1> print xX--------------------------------------------------------------------------------SELECT "A1"."DATA" "DATA","A1"."OWNER" "OWNER" FROM (SELECT "A2"."DATA" "DATA","A2"."OWNER" "OWNER" FROM "OPS$TKYTE"."MY_TABLE" "A2" WHERE "A2"."OWNER"=USER@!) "A1"Not an earth shattering new feature - but extremely useful in certain cases. I know I'll be using it when someone asks me to look at a query that looks simple but has a twenty page plan associated with it!

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How to Control Screen Layouts in LightSwitch

- by ChrisD

Visual Studio LightSwitch has a bunch of screen templates that you can use to quickly generate screens. They give you good starting points that you can customize further. When you add a new screen to your project you see a set of screen templates that you can choose from. These templates lay out all the related data you choose to put on a screen automatically for you. And don’t under estimate them; they do a great job of laying out controls in a smart way. For instance, a tab control will be used when you select more than one related set of data to display on a screen. However, you’re not limited to taking the layout as is. In fact, the screen designer is pretty flexible and allows you to create stacks of controls in a variety of configurations. You just need to visualize your screen as a series of containers that you can lay out in rows and columns. You then place controls or stacks of controls into these areas to align the screen exactly how you want. If you’re new in Visual Studio LightSwitch, you can see this tutorial. OK, Let’s start with a simple example. I have already designed my data entities for a simple order tracking system similar to the Northwind database. I also have added a Search Data Screen to search my Products already. Now I will add a new Details Screen for my Products and make it the default screen via the “Add New Screen” dialog: The screen designer picks a simple layout for me based on the single entity I chose, in this case Product. Hit F5 to run the application, select a Product on the search screen to open the Product Details Screen. Notice that it’s pretty simple because my entity is simple. Click the “Customize” button in the top right of the screen so we can start tweaking it. The left side of the screen shows the containership of controls and data bindings (called the content tree) and the right side shows the live preview with data. Notice that we have a simple layout of two rows but only one row is populated (with a vertical stack of controls in this case). The bottom row is empty. You can envision the screen like this: Each container will display a group of data that you select. For instance in the above screen, the top row is set to a vertical stack control and the group of data to display is coming from Product. So when laying out screens you need to think in terms of containers of controls bound to groups of data. To change the data to which a container is bound, select the data item next to the container: You can select the “New Group” item in order to create more containers (or controls) within the current container. For instance to totally control the layout, select the Product in the top row and hit the delete key. This will delete the vertical stack and therefore all the controls on the screen. The content tree will still have two rows, but the rows are now both empty. If you want a layout of four containers (two rows and two columns) then select “New Group” for the data item and then change the vertical stack control to “Two Columns” for both of the rows as shown here: You can keep going on and on by selecting new groups and choosing between rows or columns. Here’s a layout with 8 containers, 4 rows and 2 columns: And here is a layout with 7 content areas; one row across the top of the screen and three rows with two columns below that: When you select Choose Content and select a data item like Product it will populate all the controls within the container (row or column in a vertical stack) however you have complete control on what to display within each group. You can delete fields you don’t want to display and/or change their controls. You can also change the size of controls and how they display by changing the settings in the properties window. If you are in the Screen Designer (and not the customization mode like we are here) you can also drag-drop data items from the left-hand side of the screen to the content tree. Note, however, that not all areas of the tree will allow you to drop a data item if there is a binding already set to a different set of data. For instance you can’t drop a Customer ID into the same group as a Product if they originate from different entities. To get around this, all you need to do is create a new group and content area as shown above. Let’s take a more complex example that deals with more than just product. I want to design a complex screen that displays Products and their Category, as well as all the OrderDetails for which that product is selected. This time I will create a new screen and select List and Details, select the Products screen data, and include the related OrderDetails. However I’m going to totally change the layout so that a Product grid is at the top left and below that is the selected Product detail. Below that will be the Category text fields and image in two columns below. On the right side I want the OrderDetails grid to take up the whole right side of the screen. All this can be done in customization mode while you’re debugging the application. To do this, I first deleted all the content items in the tree and then re-created the content tree as shown in the image below. I also set the image to be larger and the description textbox to be 5 rows using the property window below the live preview. I added the green lines to indicate the containers and show how it maps to the content tree (click to enlarge): I hope this demystifies the screen designer a little bit. Remember that screen templates are excellent starting points – you can take them as-is or customize them further. It takes a little fooling around with customizing screens to get them to do exactly what you want but there are a ton of possibilities once you get the hang of it. Stay tuned for more information on how to create your own screen templates that show up in the “Add New Screen” dialog. Enjoy! The tutorial that might be interested: Adding Custom Control In LightSwitch

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Chart Filtering

- by Tim Dexter

Interesting question from a colleague this week. Can you add a filter to a chart to just show a specific set of data? In an RTF template, you need to do a little finagling in the chart definition. In an online template, a couple of clicks and you're done. RTF Build your chart as you would normally to include all the data to start with. Now flip to the Advanced tab to see the code behind the chart. Its not very pretty but with a little effort you can get it looking a little more friendly. Here's my chart showing employees and their salaries. <Graph depthAngle="50" depthRadius="8" seriesEffect="SE_AUTO_GRADIENT"> <LegendArea visible="true"/> <Title text="Executive Department Only" visible="true" horizontalAlignment="CENTER"/> <LocalGridData colCount="{count(.//G_2)}" rowCount="1"> <RowLabels> <Label>SALARY</Label> </RowLabels> <ColLabels> <xsl:for-each select=".//G_2"> <Label><xsl:value-of select="EMP_NAME"/></Label> </xsl:for-each> </ColLabels> <DataValues> <RowData> <xsl:for-each select=".//G_2"> <Cell><xsl:value-of select="SALARY"/></Cell> </xsl:for-each> </RowData> </DataValues> </LocalGridData> </Graph> Note the emboldened text. Its currently grabbing all values in the G_2 level of the data. We can use an XPATH expression to filter the data to the set we want to see. In my case I want to only see the employees that are in the Executive department. My data is structured thus: <DATA_DS> <G_1> <DEPARTMENT_NAME>Accounting</DEPARTMENT_NAME> <G_2> <MANAGER>Higgins</MANAGER> <EMPLOYEE_ID>206</EMPLOYEE_ID> <HIRE_DATE>2002-06-07T00:00:00.000-04:00</HIRE_DATE> <SALARY>8300</SALARY> <JOB_TITLE>Public Accountant</JOB_TITLE> <PARAS>11000</PARAS> <EMP_NAME>William Gietz</EMP_NAME> </G_2> So the XPATH expression Im going to use to limit the data to the Executive department would be .//G_2[../DEPARTMENT_NAME='Executive'] Note the ../ moves the parser up the XML tree to be able to test the DEPARTMENT_NAME value. I added this XPATH expression to the three instances that need it ColCount, ColLabels and RowData. Its simple enough to do. Testing your XPATH expression is easier to do using a table of data. Please note, as soon as you make changes to the chart code. Going back to the Builder tab, you'll find that everything is grayed out. I recommend you make all the changes you can via the chart dialog before updating the code. Online Template Implementing the filter is much simpler, there is a dialog box to help you out. Add you chart and fill out the various data points you want to show. then hit the Filter item in the ribbon above the chart. That will pop the filter dialog box where you can then add a filter to the chart. You can add multiple filters if needed and of course you can use the Manage Filters button to re-open and edit the filters. Pretty straightforward stuff!

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unexplainable packet drops with 5 ethernet NICs and low traffic on Ubuntu

- by jon

I'm stuck on problem where my machine started to drops packets with no sign of ANY system load or high interrupt usage after an upgrade to Ubuntu 12.04. My server is a network monitoring sensor, running Ubuntu LTS 12.04, it passively collects packets from 5 interfaces doing network intrusion type stuff. Before the upgrade I managed to collect 200+GB of packets a day while writing them to disk with around 0% packet loss depending on the day with the help of CPU affinity and NIC IRQ to CPU bindings. Now I lose a great deal of packets with none of my applications running and at very low PPS rate which a modern workstation NIC would have no trouble with. Specs: x64 Xeon 4 cores 3.2 Ghz 16 GB RAM NICs: 5 Intel Pro NICs using the e1000 driver (NAPI). [1] eth0 and eth1 are integrated NICs (in the motherboard) There are 2 other PCI-X network cards, each with 2 Ethernet ports. 3 of the interfaces are running at Gigabit Ethernet, the others are not because they're attached to hubs. Specs: [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm uptime 17:36:00 up 1:43, 2 users, load average: 0.00, 0.01, 0.05 # uname -a Linux nms 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux I also have the CPU governor set to performance mode and irqbalance off. The problem still occurs with them on. # lspci -t -vv -[0000:00]-+-00.0 Intel Corporation E7520 Memory Controller Hub +-02.0-[01-03]--+-00.0-[02]----0e.0 Dell PowerEdge Expandable RAID controller 4 | \-00.2-[03]-- +-04.0-[04]-- +-05.0-[05-07]--+-00.0-[06]----07.0 Intel Corporation 82541GI Gigabit Ethernet Controller | \-00.2-[07]----08.0 Intel Corporation 82541GI Gigabit Ethernet Controller +-06.0-[08-0a]--+-00.0-[09]--+-04.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | | \-04.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-00.2-[0a]--+-02.0 Digium, Inc. Wildcard TE210P/TE212P dual-span T1/E1/J1 card 3.3V | +-03.0 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) | \-03.1 Intel Corporation 82546EB Gigabit Ethernet Controller (Copper) +-1d.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #1 +-1d.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #2 +-1d.2 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB UHCI Controller #3 +-1d.7 Intel Corporation 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller +-1e.0-[0b]----0d.0 Advanced Micro Devices [AMD] nee ATI RV100 QY [Radeon 7000/VE] +-1f.0 Intel Corporation 82801EB/ER (ICH5/ICH5R) LPC Interface Bridge \-1f.1 Intel Corporation 82801EB/ER (ICH5/ICH5R) IDE Controller I believe the NIC nor the NIC drivers are dropping the packets because ethtool reports 0 under rx_missed_errors and rx_no_buffer_count for each interface. On the old system, if it couldn't keep up this is where the drops would be. I drop packets on multiple interfaces just about every second, usually in small increments of 2-4. I tried all these sysctl values, I'm currently using the uncommented ones. # cat /etc/sysctl.conf # high net.core.netdev_max_backlog = 3000000 net.core.rmem_max = 16000000 net.core.rmem_default = 8000000 # defaults #net.core.netdev_max_backlog = 1000 #net.core.rmem_max = 131071 #net.core.rmem_default = 163480 # moderate #net.core.netdev_max_backlog = 10000 #net.core.rmem_max = 33554432 #net.core.rmem_default = 33554432 Here's an example of an interface stats report with ethtool. They are all the same, nothing is out of the ordinary ( I think ), so I'm only going to show one: ethtool -S eth2 NIC statistics: rx_packets: 7498 tx_packets: 0 rx_bytes: 2722585 tx_bytes: 0 rx_broadcast: 327 tx_broadcast: 0 rx_multicast: 1504 tx_multicast: 0 rx_errors: 0 tx_errors: 0 tx_dropped: 0 multicast: 1504 collisions: 0 rx_length_errors: 0 rx_over_errors: 0 rx_crc_errors: 0 rx_frame_errors: 0 rx_no_buffer_count: 0 rx_missed_errors: 0 tx_aborted_errors: 0 tx_carrier_errors: 0 tx_fifo_errors: 0 tx_heartbeat_errors: 0 tx_window_errors: 0 tx_abort_late_coll: 0 tx_deferred_ok: 0 tx_single_coll_ok: 0 tx_multi_coll_ok: 0 tx_timeout_count: 0 tx_restart_queue: 0 rx_long_length_errors: 0 rx_short_length_errors: 0 rx_align_errors: 0 tx_tcp_seg_good: 0 tx_tcp_seg_failed: 0 rx_flow_control_xon: 0 rx_flow_control_xoff: 0 tx_flow_control_xon: 0 tx_flow_control_xoff: 0 rx_long_byte_count: 2722585 rx_csum_offload_good: 0 rx_csum_offload_errors: 0 alloc_rx_buff_failed: 0 tx_smbus: 0 rx_smbus: 0 dropped_smbus: 01 # ifconfig eth0 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:373348 errors:16 dropped:95 overruns:0 frame:16 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:356830572 (356.8 MB) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 00:11:43:e0:e2:8d UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:13616 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8690528 (8.6 MB) TX bytes:0 (0.0 B) eth2 Link encap:Ethernet HWaddr 00:04:23:e1:77:6a UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:7750 errors:0 dropped:471 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2780935 (2.7 MB) TX bytes:0 (0.0 B) eth3 Link encap:Ethernet HWaddr 00:04:23:e1:77:6b UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:5112 errors:0 dropped:206 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:639472 (639.4 KB) TX bytes:0 (0.0 B) eth4 Link encap:Ethernet HWaddr 00:04:23:b6:35:6c UP BROADCAST RUNNING NOARP PROMISC ALLMULTI MULTICAST MTU:1500 Metric:1 RX packets:961467 errors:0 dropped:935 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:958561305 (958.5 MB) TX bytes:0 (0.0 B) eth5 Link encap:Ethernet HWaddr 00:04:23:b6:35:6d inet addr:192.168.1.6 Bcast:192.168.1.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:4264 errors:0 dropped:16 overruns:0 frame:0 TX packets:699 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:572228 (572.2 KB) TX bytes:124456 (124.4 KB) I tried the defaults, then started to play around with settings. I wasn't using any flow control and I increased the RxDescriptor count to 4096 before the upgrade as well without any problems. # cat /etc/modprobe.d/e1000.conf options e1000 XsumRX=0,0,0,0,0 RxDescriptors=4096,4096,4096,4096,4096 FlowControl=0,0,0,0,0 debug=16 Here's my network configuration file, I turned off checksumming and various offloading mechanisms along with setting CPU affinity with heavy use interfaces getting an entire CPU and light use interfaces sharing a CPU. I used these settings prior to the upgrade without problems. # cat /etc/network/interfaces # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet manual pre-up /sbin/ethtool -G eth0 rx 4096 tx 0 pre-up /sbin/ethtool -K eth0 gro off gso off rx off pre-up /sbin/ethtool -A eth0 rx off autoneg off up ifconfig eth0 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/48/smp_affinity down ifconfig eth0 down post-down /sbin/ethtool -G eth0 rx 256 tx 256 post-down /sbin/ethtool -K eth0 gro on gso on rx on post-down /sbin/ethtool -A eth0 rx on autoneg on auto eth1 iface eth1 inet manual pre-up /sbin/ethtool -G eth1 rx 4096 tx 0 pre-up /sbin/ethtool -K eth1 gro off gso off rx off pre-up /sbin/ethtool -A eth1 rx off autoneg off up ifconfig eth1 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/49/smp_affinity down ifconfig eth1 down post-down /sbin/ethtool -G eth1 rx 256 tx 256 post-down /sbin/ethtool -K eth1 gro on gso on rx on post-down /sbin/ethtool -A eth1 rx on autoneg on auto eth2 iface eth2 inet manual pre-up /sbin/ethtool -G eth2 rx 4096 tx 0 pre-up /sbin/ethtool -K eth2 gro off gso off rx off pre-up /sbin/ethtool -A eth2 rx off autoneg off up ifconfig eth2 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "1" > /proc/irq/82/smp_affinity down ifconfig eth2 down post-down /sbin/ethtool -G eth2 rx 256 tx 256 post-down /sbin/ethtool -K eth2 gro on gso on rx on post-down /sbin/ethtool -A eth2 rx on autoneg on auto eth3 iface eth3 inet manual pre-up /sbin/ethtool -G eth3 rx 4096 tx 0 pre-up /sbin/ethtool -K eth3 gro off gso off rx off pre-up /sbin/ethtool -A eth3 rx off autoneg off up ifconfig eth3 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "2" > /proc/irq/83/smp_affinity down ifconfig eth3 down post-down /sbin/ethtool -G eth3 rx 256 tx 256 post-down /sbin/ethtool -K eth3 gro on gso on rx on post-down /sbin/ethtool -A eth3 rx on autoneg on auto eth4 iface eth4 inet manual pre-up /sbin/ethtool -G eth4 rx 4096 tx 0 pre-up /sbin/ethtool -K eth4 gro off gso off rx off pre-up /sbin/ethtool -A eth4 rx off autoneg off up ifconfig eth4 0.0.0.0 -arp promisc mtu 1500 allmulti txqueuelen 0 up post-up echo "4" > /proc/irq/77/smp_affinity down ifconfig eth4 down post-down /sbin/ethtool -G eth4 rx 256 tx 256 post-down /sbin/ethtool -K eth4 gro on gso on rx on post-down /sbin/ethtool -A eth4 rx on autoneg on auto eth5 iface eth5 inet static pre-up /etc/fw.conf address 192.168.1.1 netmask 255.255.255.0 broadcast 192.168.1.255 gateway 192.168.1.1 dns-nameservers 192.168.1.2 192.168.1.3 up ifconfig eth5 up post-up echo "8" > /proc/irq/77/smp_affinity down ifconfig eth5 down Here's a few examples of packet drops, i ran one after another, probabling totaling 3 or 4 seconds. You can see increases in the drops from the 1st and 3rd. This was a non-busy time, very little traffic. # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 505 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 225 lo: 0 eth2: 507 eth1: 0 eth5: 17 eth0: 105 eth4: 1034 # awk '{ print $1,$5 }' /proc/net/dev Inter-| face drop eth3: 227 lo: 0 eth2: 512 eth1: 0 eth5: 17 eth0: 105 eth4: 1039 I tried the pci=noacpi options. With and without, it's the same. This is what my interrupt stats looked like before the upgrade, after, with ACPI on PCI it showed multiple NICs bound to an interrupt and shared with other devices such as USB drives which I didn't like so I think i'm going to keep it with ACPI off as it's easier to designate sole purpose interrupts. Is there any advantage I would have using the default i.e. ACPI w/ PCI. ? # cat /etc/default/grub | grep CMD_LINE GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 noacpi pci=noacpi" GRUB_CMDLINE_LINUX="" # cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 0: 45 0 0 16 IO-APIC-edge timer 1: 1 0 0 7936 IO-APIC-edge i8042 2: 0 0 0 0 XT-PIC-XT-PIC cascade 6: 0 0 0 3 IO-APIC-edge floppy 8: 0 0 0 1 IO-APIC-edge rtc0 9: 0 0 0 0 IO-APIC-edge acpi 12: 0 0 0 1809 IO-APIC-edge i8042 14: 1 0 0 4498 IO-APIC-edge ata_piix 15: 0 0 0 0 IO-APIC-edge ata_piix 16: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb2 18: 0 0 0 1350 IO-APIC-fasteoi uhci_hcd:usb4, radeon 19: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb3 23: 0 0 0 4099 IO-APIC-fasteoi ehci_hcd:usb1 38: 0 0 0 61963 IO-APIC-fasteoi megaraid 48: 0 0 1002319 4 IO-APIC-fasteoi eth0 49: 0 0 38772 3 IO-APIC-fasteoi eth1 77: 0 0 130076 432159 IO-APIC-fasteoi eth4 78: 0 0 0 23917 IO-APIC-fasteoi eth5 82: 1329033 0 0 4 IO-APIC-fasteoi eth2 83: 0 4886525 0 6 IO-APIC-fasteoi eth3 NMI: 5 6 4 5 Non-maskable interrupts LOC: 61409 57076 64257 114764 Local timer interrupts SPU: 0 0 0 0 Spurious interrupts IWI: 0 0 0 0 IRQ work interrupts RES: 17956 25333 13436 14789 Rescheduling interrupts CAL: 22436 607 539 478 Function call interrupts TLB: 1525 1458 4600 4151 TLB shootdowns TRM: 0 0 0 0 Thermal event interrupts THR: 0 0 0 0 Threshold APIC interrupts MCE: 0 0 0 0 Machine check exceptions MCP: 16 16 16 16 Machine check polls ERR: 0 MIS: 0 Here's sample output of vmstat, showing the system. Barebones system right now. root@nms:~# vmstat -S m 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 14992 192 1029 0 0 56 2 419 29 1 0 99 0 0 0 0 14992 192 1029 0 0 0 0 922 27 0 0 100 0 0 0 0 14991 192 1029 0 0 0 36 763 50 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 646 35 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 722 54 0 0 100 0 0 0 0 14991 192 1029 0 0 0 0 793 27 0 0 100 0 ^C Here's dmesg output. I can't figure out why my PCI-X slots are negotiated as PCI. The network cards are all PCI-X with the exception of the integrated NICs that came with the server. In the output below it looks as if eth3 and eth2 negotiated at PCI-X speeds rather than PCI:66Mhz. Wouldn't they all drop to PCI:66Mhz? If your integrated NICs are PCI, as labeled below (eth0,eth1), then wouldn't all devices on your bus speed drop down to that slower bus speed? If not, I still don't know why only one of my NICs ( each has two ethernet ports) is labeled as PCI-X in the output below. Does that mean it is running at PCI-X speeds are is it showing that it's capable? # dmesg | grep e1000 [ 3678.349337] e1000: Intel(R) PRO/1000 Network Driver - version 7.3.21-k8-NAPI [ 3678.349342] e1000: Copyright (c) 1999-2006 Intel Corporation. [ 3678.349394] e1000 0000:06:07.0: PCI->APIC IRQ transform: INT A -> IRQ 48 [ 3678.409725] e1000 0000:06:07.0: Receive Descriptors set to 4096 [ 3678.409730] e1000 0000:06:07.0: Checksum Offload Disabled [ 3678.409734] e1000 0000:06:07.0: Flow Control Disabled [ 3678.586409] e1000 0000:06:07.0: eth0: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8c [ 3678.586419] e1000 0000:06:07.0: eth0: Intel(R) PRO/1000 Network Connection [ 3678.586642] e1000 0000:07:08.0: PCI->APIC IRQ transform: INT A -> IRQ 49 [ 3678.649854] e1000 0000:07:08.0: Receive Descriptors set to 4096 [ 3678.649859] e1000 0000:07:08.0: Checksum Offload Disabled [ 3678.649863] e1000 0000:07:08.0: Flow Control Disabled [ 3678.826436] e1000 0000:07:08.0: eth1: (PCI:66MHz:32-bit) 00:11:43:e0:e2:8d [ 3678.826444] e1000 0000:07:08.0: eth1: Intel(R) PRO/1000 Network Connection [ 3678.826627] e1000 0000:09:04.0: PCI->APIC IRQ transform: INT A -> IRQ 82 [ 3679.093266] e1000 0000:09:04.0: Receive Descriptors set to 4096 [ 3679.093271] e1000 0000:09:04.0: Checksum Offload Disabled [ 3679.093275] e1000 0000:09:04.0: Flow Control Disabled [ 3679.130239] e1000 0000:09:04.0: eth2: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6a [ 3679.130246] e1000 0000:09:04.0: eth2: Intel(R) PRO/1000 Network Connection [ 3679.130449] e1000 0000:09:04.1: PCI->APIC IRQ transform: INT B -> IRQ 83 [ 3679.397312] e1000 0000:09:04.1: Receive Descriptors set to 4096 [ 3679.397318] e1000 0000:09:04.1: Checksum Offload Disabled [ 3679.397321] e1000 0000:09:04.1: Flow Control Disabled [ 3679.434350] e1000 0000:09:04.1: eth3: (PCI-X:133MHz:64-bit) 00:04:23:e1:77:6b [ 3679.434360] e1000 0000:09:04.1: eth3: Intel(R) PRO/1000 Network Connection [ 3679.434553] e1000 0000:0a:03.0: PCI->APIC IRQ transform: INT A -> IRQ 77 [ 3679.704072] e1000 0000:0a:03.0: Receive Descriptors set to 4096 [ 3679.704077] e1000 0000:0a:03.0: Checksum Offload Disabled [ 3679.704081] e1000 0000:0a:03.0: Flow Control Disabled [ 3679.738364] e1000 0000:0a:03.0: eth4: (PCI:33MHz:64-bit) 00:04:23:b6:35:6c [ 3679.738371] e1000 0000:0a:03.0: eth4: Intel(R) PRO/1000 Network Connection [ 3679.738538] e1000 0000:0a:03.1: PCI->APIC IRQ transform: INT B -> IRQ 78 [ 3680.046060] e1000 0000:0a:03.1: eth5: (PCI:33MHz:64-bit) 00:04:23:b6:35:6d [ 3680.046067] e1000 0000:0a:03.1: eth5: Intel(R) PRO/1000 Network Connection [ 3682.132415] e1000: eth0 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.224423] e1000: eth1 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.316385] e1000: eth2 NIC Link is Up 100 Mbps Half Duplex, Flow Control: None [ 3682.408391] e1000: eth3 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.500396] e1000: eth4 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 3682.708401] e1000: eth5 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX At first I thought it was the NIC drivers but I'm not so sure. I really have no idea where else to look at the moment. Any help is greatly appreciated as I'm struggling with this. If you need more information just ask. Thanks! [1]http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/Documentation/networking/e1000.txt?v=2.6.11.8 [2] http://support.dell.com/support/edocs/systems/pe2850/en/ug/t1390aa.htm

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Optimizing transition/movement smoothness for a 2D flash game.

- by Tom

Update 6: Fenomenas suggested me to re-create everything as simple as possible. I had my doubts that this would make any difference as the algorithm remains the same, and performance did not seem to be the issue. Anyway, it was the only suggestion I got so here it is: 30 FPS: http://www.feedpostal.com/test/simple/30/SimpleMovement.html 40 FPS: http://www.feedpostal.com/test/simple/40/SimpleMovement.html 60 FPS: http://www.feedpostal.com/test/simple/60/SimpleMovement.html 100 FPS: http://www.feedpostal.com/test/simple/100/SimpleMovement.html The code: package { import flash.display.Sprite; import flash.events.Event; import flash.events.KeyboardEvent; import flash.utils.getTimer; [SWF(width="800", height="600", frameRate="40", backgroundColor="#000000")] public class SimpleMovement extends Sprite { private static const TURNING_SPEED:uint = 180; private static const MOVEMENT_SPEED:uint = 400; private static const RADIAN_DIVIDE:Number = Math.PI/180; private var playerObject:Sprite; private var shipContainer:Sprite; private var moving:Boolean = false; private var turningMode:uint = 0; private var movementTimestamp:Number = getTimer(); private var turningTimestamp:Number = movementTimestamp; public function SimpleMovement() { //step 1: create player object playerObject = new Sprite(); playerObject.graphics.lineStyle(1, 0x000000); playerObject.graphics.beginFill(0x6D7B8D); playerObject.graphics.drawRect(0, 0, 25, 50); //make it rotate around the center playerObject.x = 0 - playerObject.width / 2; playerObject.y = 0 - playerObject.height / 2; shipContainer = new Sprite(); shipContainer.addChild(playerObject); shipContainer.x = 100; shipContainer.y = 100; shipContainer.rotation = 180; addChild(shipContainer); //step 2: install keyboard hook when stage is ready addEventListener(Event.ADDED_TO_STAGE, stageReady, false, 0, true); //step 3: install rendering update poll addEventListener(Event.ENTER_FRAME, updatePoller, false, 0, true); } private function updatePoller(event:Event):void { var newTime:Number = getTimer(); //turning if (turningMode != 0) { var turningDeltaTime:Number = newTime - turningTimestamp; turningTimestamp = newTime; var rotation:Number = TURNING_SPEED * turningDeltaTime / 1000; if (turningMode == 1) shipContainer.rotation -= rotation; else shipContainer.rotation += rotation; } //movement if (moving) { var movementDeltaTime:Number = newTime - movementTimestamp; movementTimestamp = newTime; var distance:Number = MOVEMENT_SPEED * movementDeltaTime / 1000; var rAngle:Number = shipContainer.rotation * RADIAN_DIVIDE; //convert degrees to radian shipContainer.x += distance * Math.sin(rAngle); shipContainer.y -= distance * Math.cos(rAngle); } } private function stageReady(event:Event):void { //install keyboard hook stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDown, false, 0, true); stage.addEventListener(KeyboardEvent.KEY_UP, keyUp, false, 0, true); } private final function keyDown(event:KeyboardEvent):void { if ((event.keyCode == 87) && (!moving)) //87 = W { movementTimestamp = getTimer(); moving = true; } if ((event.keyCode == 65) && (turningMode != 1)) //65 = A { turningTimestamp = getTimer(); turningMode = 1; } else if ((event.keyCode == 68) && (turningMode != 2)) //68 = D { turningTimestamp = getTimer(); turningMode = 2; } } private final function keyUp(event:KeyboardEvent):void { if ((event.keyCode == 87) && (moving)) moving = false; //87 = W if (((event.keyCode == 65) || (event.keyCode == 68)) && (turningMode != 0)) turningMode = 0; //65 = A, 68 = D } } } The results were as I expected. Absolutely no improvement. I really hope that someone has another suggestion as this thing needs fixing. Also, I doubt it's my system as I have a pretty good one (8GB RAM, Q9550 QuadCore intel, ATI Radeon 4870 512MB). Also, everyone else I asked so far had the same issue with my client. Update 5: another example of a smooth flash game just to demonstrate that my movement definitely is different! See http://www.spel.nl/game/bumpercraft.html Update 4: I traced the time before rendering (EVENT.RENDER) and right after rendering (EVENT.ENTER_FRAME), the results: rendering took: 14 ms rendering took: 14 ms rendering took: 12 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 14 ms rendering took: 12 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 14 ms rendering took: 12 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 14 ms rendering took: 14 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 24 ms rendering took: 18 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 232 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms rendering took: 14 ms rendering took: 16 ms rendering took: 12 ms rendering took: 14 ms rendering took: 12 ms The range is 12-16 ms. During these differences, the shocking/warping/flickering movement was already going on. There is also 1 peak of 232ms, at this time there was a relatively big warp. This is however not the biggest problme, the biggest problem are the continuous small warps during normal movement. Does this give anyone a clue? Update 3: After testing, I know that the following factors are not causing my problem: Bitmap's quality - changed with photoshop to an uglier 8 colours optimized graphic, no improvement at all. Constant rotation of image while turning - disabled it, no improvement at all Browser rendering - tried to use the flash player standalone, no improvement at all I am 100% convinced that the problem lies in either my code or in my algorithm. Please, help me out. It has been almost two weeks (1 week that I asked this question on SO) now and I still have to get my golden answer. Update 1: see bottom for full flex project source and a live demo demonstrating my problem. I'm working on a 2d flash game. Player ships are created as an object: ships[id] = new GameShip(); When movement and rotation information is available, this is being directed to the corresponding ship: ships[id].setMovementMode(1); //move forward Now, within this GameShip object movement works using the "Event.ENTER_FRAME" event: addEventListener(Event.ENTER_FRAME, movementHandler); The following function is then being run: private final function movementHandler(event:Event):void { var newTimeStamp:uint = UtilLib.getTimeStamp(); //set current timeStamp var distance:Number = (newTimeStamp - movementTimeStamp) / 1000 * movementSpeed; //speed = x pixels forward every 1 second movementTimeStamp = newTimeStamp; //update old timeStamp var diagonalChange:Array = getDiagonalChange(movementAngle, distance); //the diagonal position update based on angle and distance charX += diagonalChange[0]; charY += diagonalChange[1]; if (shipContainer) { //when the container is ready to be worked with shipContainer.x = charX; shipContainer.y = charY; } } private final function getDiagonalChange(angle:Number, distance:Number):Array { var rAngle:Number = angle * Math.PI/180; //convert degrees to radian return [Math.sin(rAngle) * distance, (Math.cos(rAngle) * distance) * -1]; } When the object is no longer moving, the event listener will be removed. The same method is being used for rotation. Everything works almost perfect. I've set the project's target FPS to 100 and created a FPS counter. According to the FPS counter, the average FPS in firefox is around 100, while the top is 1000 and the bottom is 22. I think that the bottom and top FPSs are only happening during the initialization of the client (startup). The problem is that the ship appears to be almost perfectly smooth, while it should be just that without the "almost" part. It's almost as if the ship is "flickering" very very fast, you can't actually see it but it's hard to focus on the object while it's moving with your eyes. Also, every now and then, there seems to be a bit of a framerate spike, as if the client is skipping a couple of frames, you then see it quickly warp. It is very difficult to explain what the real problem is, but in general it's that the movement is not perfectly smooth. So, do you have any suggestions on how to make the movement or transition of objects perfectly smooth? Update 1: I re-created the client to demonstrate my problem. Please check it out. The client: http://feedpostal.com/test/MovementTest.html The Actionscript Project (full source): http://feedpostal.com/test/MovementTest.rar An example of a smooth flash game (not created by me): http://www.gamesforwork.com/games/swf/Mission%20Racing_august_10th_2009.swf It took me a pretty long time to recreate this client side version, I hope this will help with solving the problem. Please note: yes, it is actually pretty smooth. But it is definitely not smooth enough.

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Replacing instructions in a method's MethodBody

- by Alix

Hi, (First of all, this is a very lengthy post, but don't worry: I've already implemented all of it, I'm just asking your opinion.) I'm having trouble implementing the following; I'd appreciate some help: I get a Type as parameter. I define a subclass using reflection. Notice that I don't intend to modify the original type, but create a new one. I create a property per field of the original class, like so: public class OriginalClass { private int x; } public class Subclass : OriginalClass { private int x; public int X { get { return x; } set { x = value; } } } For every method of the superclass, I create an analogous method in the subclass. The method's body must be the same except that I replace the instructions ldfld x with callvirt this.get_X, that is, instead of reading from the field directly I call the get accessor. I'm having trouble with step 4. I know you're not supposed to manipulate code like this, but I really need to. Here's what I've tried: Attempt #1: Use Mono.Cecil. This would allow me to parse the body of the method into human-readable Instructions, and easily replace instructions. However, the original type isn't in a .dll file, so I can't find a way to load it with Mono.Cecil. Writing the type to a .dll, then load it, then modify it and write the new type to disk (which I think is the way you create a type with Mono.Cecil), and then load it seems like a huge overhead. Attempt #2: Use Mono.Reflection. This would also allow me to parse the body into Instructions, but then I have no support for replacing instructions. I've implemented a very ugly and inefficient solution using Mono.Reflection, but it doesn't yet support methods that contain try-catch statements (although I guess I can implement this) and I'm concerned that there may be other scenarios in which it won't work, since I'm using the ILGenerator in a somewhat unusual way. Also, it's very ugly ;). Here's what I've done: private void TransformMethod(MethodInfo methodInfo) { // Create a method with the same signature. ParameterInfo[] paramList = methodInfo.GetParameters(); Type[] args = new Type[paramList.Length]; for (int i = 0; i < args.Length; i++) { args[i] = paramList[i].ParameterType; } MethodBuilder methodBuilder = typeBuilder.DefineMethod( methodInfo.Name, methodInfo.Attributes, methodInfo.ReturnType, args); ILGenerator ilGen = methodBuilder.GetILGenerator(); // Declare the same local variables as in the original method. IList<LocalVariableInfo> locals = methodInfo.GetMethodBody().LocalVariables; foreach (LocalVariableInfo local in locals) { ilGen.DeclareLocal(local.LocalType); } // Get readable instructions. IList<Instruction> instructions = methodInfo.GetInstructions(); // I first need to define labels for every instruction in case I // later find a jump to that instruction. Once the instruction has // been emitted I cannot label it, so I'll need to do it in advance. // Since I'm doing a first pass on the method's body anyway, I could // instead just create labels where they are truly needed, but for // now I'm using this quick fix. Dictionary<int, Label> labels = new Dictionary<int, Label>(); foreach (Instruction instr in instructions) { labels[instr.Offset] = ilGen.DefineLabel(); } foreach (Instruction instr in instructions) { // Mark this instruction with a label, in case there's a branch // instruction that jumps here. ilGen.MarkLabel(labels[instr.Offset]); // If this is the instruction that I want to replace (ldfld x)... if (instr.OpCode == OpCodes.Ldfld) { // ...get the get accessor for the accessed field (get_X()) // (I have the accessors in a dictionary; this isn't relevant), MethodInfo safeReadAccessor = dataMembersSafeAccessors[((FieldInfo) instr.Operand).Name][0]; // ...instead of emitting the original instruction (ldfld x), // emit a call to the get accessor, ilGen.Emit(OpCodes.Callvirt, safeReadAccessor); // Else (it's any other instruction), reemit the instruction, unaltered. } else { Reemit(instr, ilGen, labels); } } } And here comes the horrible, horrible Reemit method: private void Reemit(Instruction instr, ILGenerator ilGen, Dictionary<int, Label> labels) { // If the instruction doesn't have an operand, emit the opcode and return. if (instr.Operand == null) { ilGen.Emit(instr.OpCode); return; } // Else (it has an operand)... // If it's a branch instruction, retrieve the corresponding label (to // which we want to jump), emit the instruction and return. if (instr.OpCode.FlowControl == FlowControl.Branch) { ilGen.Emit(instr.OpCode, labels[Int32.Parse(instr.Operand.ToString())]); return; } // Otherwise, simply emit the instruction. I need to use the right // Emit call, so I need to cast the operand to its type. Type operandType = instr.Operand.GetType(); if (typeof(byte).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (byte) instr.Operand); else if (typeof(double).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (double) instr.Operand); else if (typeof(float).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (float) instr.Operand); else if (typeof(int).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (int) instr.Operand); ... // you get the idea. This is a pretty long method, all like this. } Branch instructions are a special case because instr.Operand is SByte, but Emit expects an operand of type Label. Hence the need for the Dictionary labels. As you can see, this is pretty horrible. What's more, it doesn't work in all cases, for instance with methods that contain try-catch statements, since I haven't emitted them using methods BeginExceptionBlock, BeginCatchBlock, etc, of ILGenerator. This is getting complicated. I guess I can do it: MethodBody has a list of ExceptionHandlingClause that should contain the necessary information to do this. But I don't like this solution anyway, so I'll save this as a last-resort solution. Attempt #3: Go bare-back and just copy the byte array returned by MethodBody.GetILAsByteArray(), since I only want to replace a single instruction for another single instruction of the same size that produces the exact same result: it loads the same type of object on the stack, etc. So there won't be any labels shifting and everything should work exactly the same. I've done this, replacing specific bytes of the array and then calling MethodBuilder.CreateMethodBody(byte[], int), but I still get the same error with exceptions, and I still need to declare the local variables or I'll get an error... even when I simply copy the method's body and don't change anything. So this is more efficient but I still have to take care of the exceptions, etc. Sigh. Here's the implementation of attempt #3, in case anyone is interested: private void TransformMethod(MethodInfo methodInfo, Dictionary<string, MethodInfo[]> dataMembersSafeAccessors, ModuleBuilder moduleBuilder) { ParameterInfo[] paramList = methodInfo.GetParameters(); Type[] args = new Type[paramList.Length]; for (int i = 0; i < args.Length; i++) { args[i] = paramList[i].ParameterType; } MethodBuilder methodBuilder = typeBuilder.DefineMethod( methodInfo.Name, methodInfo.Attributes, methodInfo.ReturnType, args); ILGenerator ilGen = methodBuilder.GetILGenerator(); IList<LocalVariableInfo> locals = methodInfo.GetMethodBody().LocalVariables; foreach (LocalVariableInfo local in locals) { ilGen.DeclareLocal(local.LocalType); } byte[] rawInstructions = methodInfo.GetMethodBody().GetILAsByteArray(); IList<Instruction> instructions = methodInfo.GetInstructions(); int k = 0; foreach (Instruction instr in instructions) { if (instr.OpCode == OpCodes.Ldfld) { MethodInfo safeReadAccessor = dataMembersSafeAccessors[((FieldInfo) instr.Operand).Name][0]; // Copy the opcode: Callvirt. byte[] bytes = toByteArray(OpCodes.Callvirt.Value); for (int m = 0; m < OpCodes.Callvirt.Size; m++) { rawInstructions[k++] = bytes[put.Length - 1 - m]; } // Copy the operand: the accessor's metadata token. bytes = toByteArray(moduleBuilder.GetMethodToken(safeReadAccessor).Token); for (int m = instr.Size - OpCodes.Ldfld.Size - 1; m >= 0; m--) { rawInstructions[k++] = bytes[m]; } // Skip this instruction (do not replace it). } else { k += instr.Size; } } methodBuilder.CreateMethodBody(rawInstructions, rawInstructions.Length); } private static byte[] toByteArray(int intValue) { byte[] intBytes = BitConverter.GetBytes(intValue); if (BitConverter.IsLittleEndian) Array.Reverse(intBytes); return intBytes; } private static byte[] toByteArray(short shortValue) { byte[] intBytes = BitConverter.GetBytes(shortValue); if (BitConverter.IsLittleEndian) Array.Reverse(intBytes); return intBytes; } (I know it isn't pretty. Sorry. I put it quickly together to see if it would work.) I don't have much hope, but can anyone suggest anything better than this? Sorry about the extremely lengthy post, and thanks.

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Exporting a non public Type through public API

- by sachin

I am trying to follow Trees tutorial at: http://cslibrary.stanford.edu/110/BinaryTrees.html Here is the code I have written so far: package trees.bst; import java.util.ArrayList; import java.util.List; import java.util.StringTokenizer; /** * * @author sachin */ public class BinarySearchTree { Node root = null; class Node { Node left = null; Node right = null; int data = 0; public Node(int data) { this.left = null; this.right = null; this.data = data; } } public void insert(int data) { root = insert(data, root); } public boolean lookup(int data) { return lookup(data, root); } public void buildTree(int numNodes) { for (int i = 0; i < numNodes; i++) { int num = (int) (Math.random() * 10); System.out.println("Inserting number:" + num); insert(num); } } public int size() { return size(root); } public int maxDepth() { return maxDepth(root); } public int minValue() { return minValue(root); } public int maxValue() { return maxValue(root); } public void printTree() { //inorder traversal System.out.println("inorder traversal:"); printTree(root); System.out.println("\n--------------"); } public void printPostorder() { //inorder traversal System.out.println("printPostorder traversal:"); printPostorder(root); System.out.println("\n--------------"); } public int buildTreeFromOutputString(String op) { root = null; int i = 0; StringTokenizer st = new StringTokenizer(op); while (st.hasMoreTokens()) { String stNum = st.nextToken(); int num = Integer.parseInt(stNum); System.out.println("buildTreeFromOutputString: Inserting number:" + num); insert(num); i++; } return i; } public boolean hasPathSum(int pathsum) { return hasPathSum(pathsum, root); } public void mirror() { mirror(root); } public void doubleTree() { doubleTree(root); } public boolean sameTree(BinarySearchTree bst) { //is this tree same as another given tree? return sameTree(this.root, bst.getRoot()); } public void printPaths() { if (root == null) { System.out.println("print path sum: tree is empty"); } List pathSoFar = new ArrayList(); printPaths(root, pathSoFar); } ///-------------------------------------------Public helper functions public Node getRoot() { return root; } //Exporting a non public Type through public API ///-------------------------------------------Helper Functions private boolean isLeaf(Node node) { if (node == null) { return false; } if (node.left == null && node.right == null) { return true; } return false; } ///----------------------------------------------------------- private boolean sameTree(Node n1, Node n2) { if ((n1 == null && n2 == null)) { return true; } else { if ((n1 == null || n2 == null)) { return false; } else { if ((n1.data == n2.data)) { return (sameTree(n1.left, n2.left) && sameTree(n1.right, n2.right)); } } } return false; } private void doubleTree(Node node) { //create a copy //bypass the copy to continue looping if (node == null) { return; } Node copyNode = new Node(node.data); Node temp = node.left; node.left = copyNode; copyNode.left = temp; doubleTree(copyNode.left); doubleTree(node.right); } private void mirror(Node node) { if (node == null) { return; } Node temp = node.left; node.left = node.right; node.right = temp; mirror(node.left); mirror(node.right); } private void printPaths(Node node, List pathSoFar) { if (node == null) { return; } pathSoFar.add(node.data); if (isLeaf(node)) { System.out.println("path in tree:" + pathSoFar); pathSoFar.remove(pathSoFar.lastIndexOf(node.data)); //only the current node, a node.data may be duplicated return; } else { printPaths(node.left, pathSoFar); printPaths(node.right, pathSoFar); } } private boolean hasPathSum(int pathsum, Node node) { if (node == null) { return false; } int val = pathsum - node.data; boolean ret = false; if (val == 0 && isLeaf(node)) { ret = true; } else if (val == 0 && !isLeaf(node)) { ret = false; } else if (val != 0 && isLeaf(node)) { ret = false; } else if (val != 0 && !isLeaf(node)) { //recurse further ret = hasPathSum(val, node.left) || hasPathSum(val, node.right); } return ret; } private void printPostorder(Node node) { //inorder traversal if (node == null) { return; } printPostorder(node.left); printPostorder(node.right); System.out.print(" " + node.data); } private void printTree(Node node) { //inorder traversal if (node == null) { return; } printTree(node.left); System.out.print(" " + node.data); printTree(node.right); } private int minValue(Node node) { if (node == null) { //error case: this is not supported return -1; } if (node.left == null) { return node.data; } else { return minValue(node.left); } } private int maxValue(Node node) { if (node == null) { //error case: this is not supported return -1; } if (node.right == null) { return node.data; } else { return maxValue(node.right); } } private int maxDepth(Node node) { if (node == null || (node.left == null && node.right == null)) { return 0; } int ldepth = 1 + maxDepth(node.left); int rdepth = 1 + maxDepth(node.right); if (ldepth > rdepth) { return ldepth; } else { return rdepth; } } private int size(Node node) { if (node == null) { return 0; } return 1 + size(node.left) + size(node.right); } private Node insert(int data, Node node) { if (node == null) { node = new Node(data); } else if (data <= node.data) { node.left = insert(data, node.left); } else { node.right = insert(data, node.right); } //control should never reach here; return node; } private boolean lookup(int data, Node node) { if (node == null) { return false; } if (node.data == data) { return true; } if (data < node.data) { return lookup(data, node.left); } else { return lookup(data, node.right); } } public static void main(String[] args) { BinarySearchTree bst = new BinarySearchTree(); int treesize = 5; bst.buildTree(treesize); //treesize = bst.buildTreeFromOutputString("4 4 4 6 7"); treesize = bst.buildTreeFromOutputString("3 4 6 3 6"); //treesize = bst.buildTreeFromOutputString("10"); for (int i = 0; i < treesize; i++) { System.out.println("Searching:" + i + " found:" + bst.lookup(i)); } System.out.println("tree size:" + bst.size()); System.out.println("maxDepth :" + bst.maxDepth()); System.out.println("minvalue :" + bst.minValue()); System.out.println("maxvalue :" + bst.maxValue()); bst.printTree(); bst.printPostorder(); int pathSum = 10; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); pathSum = 6; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); pathSum = 19; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); bst.printPaths(); bst.printTree(); //bst.mirror(); System.out.println("Tree after mirror function:"); bst.printTree(); //bst.doubleTree(); System.out.println("Tree after double function:"); bst.printTree(); System.out.println("tree size:" + bst.size()); System.out.println("Same tree:" + bst.sameTree(bst)); BinarySearchTree bst2 = new BinarySearchTree(); bst2.buildTree(treesize); treesize = bst2.buildTreeFromOutputString("3 4 6 3 6"); bst2.printTree(); System.out.println("Same tree:" + bst.sameTree(bst2)); System.out.println("---"); } } Now the problem is that netbeans shows Warning: Exporting a non public Type through public API for function getRoot(). I write this function to get root of tree to be used in sameTree() function, to help comparison of "this" with given tree. Perhaps this is a OOP design issue... How should I restructure the above code that I do not get this warning and what is the concept I am missing here?

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ubuntu: sem_timedwait not waking (C)

- by gillez

I have 3 processes which need to be synchronized. Process one does something then wakes process two and sleeps, which does something then wakes process three and sleeps, which does something and wakes process one and sleeps. The whole loop is timed to run around 25hz (caused by an external sync into process one before it triggers process two in my "real" application). I use sem_post to trigger (wake) each process, and sem_timedwait() to wait for the trigger. This all works successfully for several hours. However at some random time (usually after somewhere between two and four hours), one of the processes starts timing out in sem_timedwait(), even though I am sure the semaphore is being triggered with sem_post(). To prove this I even use sem_getvalue() immediately after the timeout, and the value is 1, so the timedwait should have been triggered. Please see following code: #include <stdio.h> #include <time.h> #include <string.h> #include <errno.h> #include <semaphore.h> sem_t trigger_sem1, trigger_sem2, trigger_sem3; // The main thread process. Called three times with a different num arg - 1, 2 or 3. void *thread(void *arg) { int num = (int) arg; sem_t *wait, *trigger; int val, retval; struct timespec ts; struct timeval tv; switch (num) { case 1: wait = &trigger_sem1; trigger = &trigger_sem2; break; case 2: wait = &trigger_sem2; trigger = &trigger_sem3; break; case 3: wait = &trigger_sem3; trigger = &trigger_sem1; break; } while (1) { // The first thread delays by 40ms to time the whole loop. // This is an external sync in the real app. if (num == 1) usleep(40000); // print sem value before we wait. If this is 1, sem_timedwait() will // return immediately, otherwise it will block until sem_post() is called on this sem. sem_getvalue(wait, &val); printf("sem%d wait sync sem%d. val before %d\n", num, num, val); // get current time and add half a second for timeout. gettimeofday(&tv, NULL); ts.tv_sec = tv.tv_sec; ts.tv_nsec = (tv.tv_usec + 500000); // add half a second if (ts.tv_nsec > 1000000) { ts.tv_sec++; ts.tv_nsec -= 1000000; } ts.tv_nsec *= 1000; /* convert to nanosecs */ retval = sem_timedwait(wait, &ts); if (retval == -1) { // timed out. Print value of sem now. This should be 0, otherwise sem_timedwait // would have woken before timeout (unless the sem_post happened between the // timeout and this call to sem_getvalue). sem_getvalue(wait, &val); printf("!!!!!! sem%d sem_timedwait failed: %s, val now %d\n", num, strerror(errno), val); } else printf("sem%d wakeup.\n", num); // get value of semaphore to trigger. If it's 1, don't post as it has already been // triggered and sem_timedwait on this sem *should* not block. sem_getvalue(trigger, &val); if (val <= 0) { printf("sem%d send sync sem%d. val before %d\n", num, (num == 3 ? 1 : num+1), val); sem_post(trigger); } else printf("!! sem%d not sending sync, val %d\n", num, val); } } int main(int argc, char *argv[]) { pthread_t t1, t2, t3; // create semaphores. val of sem1 is 1 to trigger straight away and start the whole ball rolling. if (sem_init(&trigger_sem1, 0, 1) == -1) perror("Error creating trigger_listman semaphore"); if (sem_init(&trigger_sem2, 0, 0) == -1) perror("Error creating trigger_comms semaphore"); if (sem_init(&trigger_sem3, 0, 0) == -1) perror("Error creating trigger_vws semaphore"); pthread_create(&t1, NULL, thread, (void *) 1); pthread_create(&t2, NULL, thread, (void *) 2); pthread_create(&t3, NULL, thread, (void *) 3); pthread_join(t1, NULL); pthread_join(t2, NULL); pthread_join(t3, NULL); } The following output is printed when the program is running correctly (at the start and for a random but long time after). The value of sem1 is always 1 before thread1 waits as it sleeps for 40ms, by which time sem3 has triggered it, so it wakes straight away. The other two threads wait until the semaphore is received from the previous thread. [...] sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 sem2 wakeup. sem2 send sync sem3. val before 0 sem2 wait sync sem2. val before 0 sem3 wakeup. sem3 send sync sem1. val before 0 sem3 wait sync sem3. val before 0 sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 [...] However, after a few hours, one of the threads begins to timeout. I can see from the output that the semaphore is being triggered, and when I print the value after the timeout is is 1. So sem_timedwait should have woken up well before the timeout. I would never expect the value of the semaphore to be 1 after the timeout, save for the very rare occasion (almost certainly never but it's possible) when the trigger happens after the timeout but before I call sem_getvalue. Also, once it begins to fail, every sem_timedwait() on that semaphore also fails in the same way. See the following output, which I've line-numbered: 01 sem3 wait sync sem3. val before 0 02 sem1 wakeup. 03 sem1 send sync sem2. val before 0 04 sem2 wakeup. 05 sem2 send sync sem3. val before 0 06 sem2 wait sync sem2. val before 0 07 sem1 wait sync sem1. val before 0 08 !!!!!! sem3 sem_timedwait failed: Connection timed out, val now 1 09 sem3 send sync sem1. val before 0 10 sem3 wait sync sem3. val before 1 11 sem3 wakeup. 12 !! sem3 not sending sync, val 1 13 sem3 wait sync sem3. val before 0 14 sem1 wakeup. [...] On line 1, thread 3 (which I have confusingly called sem1 in the printf) waits for sem3 to be triggered. On line 5, sem2 calls sem_post for sem3. However, line 8 shows sem3 timing out, but the value of the semaphore is 1. thread3 then triggers sem1 and waits again (10). However, because the value is already 1, it wakes straight away. It doesn't send sem1 again as this has all happened before control is given to thread1, however it then waits again (val is now 0) and sem1 wakes up. This now repeats for ever, sem3 always timing out and showing that the value is 1. So, my question is why does sem3 timeout, even though the semaphore has been triggered and the value is clearly 1? I would never expect to see line 08 in the output. If it times out (because, say thread 2 has crashed or is taking too long), the value should be 0. And why does it work fine for 3 or 4 hours first before getting into this state? This is using Ubuntu 9.4 with kernel 2.6.28. The same procedure has been working properly on Redhat and Fedora. But I'm now trying to port to ubuntu! Thanks for any advice, Giles

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Inserting instructions into method.

- by Alix

Hi, (First of all, this is a very lengthy post, but don't worry: I've already implemented all of it, I'm just asking your opinion.) I'm having trouble implementing the following; I'd appreciate some help: I get a Type as parameter. I define a subclass using reflection. Notice that I don't intend to modify the original type, but create a new one. I create a property per field of the original class, like so: [- ignore this text here; I had to add something or the formatting wouldn't work <-] public class OriginalClass { private int x; } public class Subclass : OriginalClass { private int x; public int X { get { return x; } set { x = value; } } } [This is number 4! Numbered lists don't work if you add code in between; sorry] For every method of the superclass, I create an analogous method in the subclass. The method's body must be the same except that I replace the instructions ldfld x with callvirt this.get_X, that is, instead of reading from the field directly I call the get accessor. I'm having trouble with step 4. I know you're not supposed to manipulate code like this, but I really need to. Here's what I've tried: Attempt #1: Use Mono.Cecil. This would allow me to parse the body of the method into human-readable Instructions, and easily replace instructions. However, the original type isn't in a .dll file, so I can't find a way to load it with Mono.Cecil. Writing the type to a .dll, then load it, then modify it and write the new type to disk (which I think is the way you create a type with Mono.Cecil), and then load it seems like a huge overhead. Attempt #2: Use Mono.Reflection. This would also allow me to parse the body into Instructions, but then I have no support for replacing instructions. I've implemented a very ugly and inefficient solution using Mono.Reflection, but it doesn't yet support methods that contain try-catch statements (although I guess I can implement this) and I'm concerned that there may be other scenarios in which it won't work, since I'm using the ILGenerator in a somewhat unusual way. Also, it's very ugly ;). Here's what I've done: private void TransformMethod(MethodInfo methodInfo) { // Create a method with the same signature. ParameterInfo[] paramList = methodInfo.GetParameters(); Type[] args = new Type[paramList.Length]; for (int i = 0; i < args.Length; i++) { args[i] = paramList[i].ParameterType; } MethodBuilder methodBuilder = typeBuilder.DefineMethod( methodInfo.Name, methodInfo.Attributes, methodInfo.ReturnType, args); ILGenerator ilGen = methodBuilder.GetILGenerator(); // Declare the same local variables as in the original method. IList<LocalVariableInfo> locals = methodInfo.GetMethodBody().LocalVariables; foreach (LocalVariableInfo local in locals) { ilGen.DeclareLocal(local.LocalType); } // Get readable instructions. IList<Instruction> instructions = methodInfo.GetInstructions(); // I first need to define labels for every instruction in case I // later find a jump to that instruction. Once the instruction has // been emitted I cannot label it, so I'll need to do it in advance. // Since I'm doing a first pass on the method's body anyway, I could // instead just create labels where they are truly needed, but for // now I'm using this quick fix. Dictionary<int, Label> labels = new Dictionary<int, Label>(); foreach (Instruction instr in instructions) { labels[instr.Offset] = ilGen.DefineLabel(); } foreach (Instruction instr in instructions) { // Mark this instruction with a label, in case there's a branch // instruction that jumps here. ilGen.MarkLabel(labels[instr.Offset]); // If this is the instruction that I want to replace (ldfld x)... if (instr.OpCode == OpCodes.Ldfld) { // ...get the get accessor for the accessed field (get_X()) // (I have the accessors in a dictionary; this isn't relevant), MethodInfo safeReadAccessor = dataMembersSafeAccessors[((FieldInfo) instr.Operand).Name][0]; // ...instead of emitting the original instruction (ldfld x), // emit a call to the get accessor, ilGen.Emit(OpCodes.Callvirt, safeReadAccessor); // Else (it's any other instruction), reemit the instruction, unaltered. } else { Reemit(instr, ilGen, labels); } } } And here comes the horrible, horrible Reemit method: private void Reemit(Instruction instr, ILGenerator ilGen, Dictionary<int, Label> labels) { // If the instruction doesn't have an operand, emit the opcode and return. if (instr.Operand == null) { ilGen.Emit(instr.OpCode); return; } // Else (it has an operand)... // If it's a branch instruction, retrieve the corresponding label (to // which we want to jump), emit the instruction and return. if (instr.OpCode.FlowControl == FlowControl.Branch) { ilGen.Emit(instr.OpCode, labels[Int32.Parse(instr.Operand.ToString())]); return; } // Otherwise, simply emit the instruction. I need to use the right // Emit call, so I need to cast the operand to its type. Type operandType = instr.Operand.GetType(); if (typeof(byte).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (byte) instr.Operand); else if (typeof(double).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (double) instr.Operand); else if (typeof(float).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (float) instr.Operand); else if (typeof(int).IsAssignableFrom(operandType)) ilGen.Emit(instr.OpCode, (int) instr.Operand); ... // you get the idea. This is a pretty long method, all like this. } Branch instructions are a special case because instr.Operand is SByte, but Emit expects an operand of type Label. Hence the need for the Dictionary labels. As you can see, this is pretty horrible. What's more, it doesn't work in all cases, for instance with methods that contain try-catch statements, since I haven't emitted them using methods BeginExceptionBlock, BeginCatchBlock, etc, of ILGenerator. This is getting complicated. I guess I can do it: MethodBody has a list of ExceptionHandlingClause that should contain the necessary information to do this. But I don't like this solution anyway, so I'll save this as a last-resort solution. Attempt #3: Go bare-back and just copy the byte array returned by MethodBody.GetILAsByteArray(), since I only want to replace a single instruction for another single instruction of the same size that produces the exact same result: it loads the same type of object on the stack, etc. So there won't be any labels shifting and everything should work exactly the same. I've done this, replacing specific bytes of the array and then calling MethodBuilder.CreateMethodBody(byte[], int), but I still get the same error with exceptions, and I still need to declare the local variables or I'll get an error... even when I simply copy the method's body and don't change anything. So this is more efficient but I still have to take care of the exceptions, etc. Sigh. Here's the implementation of attempt #3, in case anyone is interested: private void TransformMethod(MethodInfo methodInfo, Dictionary<string, MethodInfo[]> dataMembersSafeAccessors, ModuleBuilder moduleBuilder) { ParameterInfo[] paramList = methodInfo.GetParameters(); Type[] args = new Type[paramList.Length]; for (int i = 0; i < args.Length; i++) { args[i] = paramList[i].ParameterType; } MethodBuilder methodBuilder = typeBuilder.DefineMethod( methodInfo.Name, methodInfo.Attributes, methodInfo.ReturnType, args); ILGenerator ilGen = methodBuilder.GetILGenerator(); IList<LocalVariableInfo> locals = methodInfo.GetMethodBody().LocalVariables; foreach (LocalVariableInfo local in locals) { ilGen.DeclareLocal(local.LocalType); } byte[] rawInstructions = methodInfo.GetMethodBody().GetILAsByteArray(); IList<Instruction> instructions = methodInfo.GetInstructions(); int k = 0; foreach (Instruction instr in instructions) { if (instr.OpCode == OpCodes.Ldfld) { MethodInfo safeReadAccessor = dataMembersSafeAccessors[((FieldInfo) instr.Operand).Name][0]; byte[] bytes = toByteArray(OpCodes.Callvirt.Value); for (int m = 0; m < OpCodes.Callvirt.Size; m++) { rawInstructions[k++] = bytes[put.Length - 1 - m]; } bytes = toByteArray(moduleBuilder.GetMethodToken(safeReadAccessor).Token); for (int m = instr.Size - OpCodes.Ldfld.Size - 1; m >= 0; m--) { rawInstructions[k++] = bytes[m]; } } else { k += instr.Size; } } methodBuilder.CreateMethodBody(rawInstructions, rawInstructions.Length); } private static byte[] toByteArray(int intValue) { byte[] intBytes = BitConverter.GetBytes(intValue); if (BitConverter.IsLittleEndian) Array.Reverse(intBytes); return intBytes; } private static byte[] toByteArray(short shortValue) { byte[] intBytes = BitConverter.GetBytes(shortValue); if (BitConverter.IsLittleEndian) Array.Reverse(intBytes); return intBytes; } (I know it isn't pretty. Sorry. I put it quickly together to see if it would work.) I don't have much hope, but can anyone suggest anything better than this? Sorry about the extremely lengthy post, and thanks.

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