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  • Installing CUDA on Ubuntu 12.04 with nvidia driver 295.59

    - by johnmcd
    I have been trying to get cuda to run on a nvidia gt 650m based laptop. I am running Ubuntu 12.04 with the nvidia 295.59 driver. Also, my laptop uses Optimus so I have install the driver via bumblebee. Bumblebee is not working correctly yet -- however I believe it is possible to install CUDA independently. To install CUDA I have followed the instructions detailed here: How can I get nVidia CUDA or OpenCL working on a laptop with nVidia discrete card/Intel Integrated Graphics? However I am still running into problem building the sdk. I made the changes specified at the above link in common.mk, but I got the following (snippet) from the build process: make[2]: Entering directory `/home/john/NVIDIA_GPU_Computing_SDK/C/src/fluidsGL' /usr/bin/ld: warning: libnvidia-tls.so.302.17, needed by /usr/lib/nvidia-current/libGL.so, not found (try using -rpath or -rpath-link) /usr/bin/ld: warning: libnvidia-glcore.so.302.17, needed by /usr/lib/nvidia-current/libGL.so, not found (try using -rpath or -rpath-link) /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv018tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv012glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv017glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv012tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv015tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv019tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv000glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv017tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv013tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv013glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv018glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv022tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv007tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv009tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv020tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv014glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv015glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv016tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv001glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv006tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv021tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv011tls' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv020glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv019glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv002glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv021glcore' /usr/lib/nvidia-current/libGL.so: undefined reference to `_nv014tls' collect2: ld returned 1 exit status make[2]: *** [../../bin/linux/release/fluidsGL] Error 1 make[2]: Leaving directory `/home/john/NVIDIA_GPU_Computing_SDK/C/src/fluidsGL' make[1]: *** [src/fluidsGL/Makefile.ph_build] Error 2 make[1]: Leaving directory `/home/john/NVIDIA_GPU_Computing_SDK/C' make: *** [all] Error 2 The libraries that ld warns about are on my system and are installed on the system: $ locate libnvidia-tls.so.302.17 libnvidia-glcore.so.302.17 /usr/lib/nvidia-current/libnvidia-glcore.so.302.17 /usr/lib/nvidia-current/libnvidia-tls.so.302.17 /usr/lib/nvidia-current/tls/libnvidia-tls.so.302.17 /usr/lib32/nvidia-current/libnvidia-glcore.so.302.17 /usr/lib32/nvidia-current/libnvidia-tls.so.302.17 /usr/lib32/nvidia-current/tls/libnvidia-tls.so.302.17 however /usr/lib/nvidia-current and /usr/lib32/nvidia-current are not being picked up by ldconfig. I have tried adding them by adding a file to /etc/ld.so.conf.d/ which gets past this error, however now I am getting the following error: make[2]: Entering directory `/home/john/NVIDIA_GPU_Computing_SDK/C/src/deviceQueryDrv' cc1plus: warning: command line option ‘-Wimplicit’ is valid for C/ObjC but not for C++ [enabled by default] obj/x86_64/release/deviceQueryDrv.cpp.o: In function `main': deviceQueryDrv.cpp:(.text.startup+0x5f): undefined reference to `cuInit' deviceQueryDrv.cpp:(.text.startup+0x99): undefined reference to `cuDeviceGetCount' deviceQueryDrv.cpp:(.text.startup+0x10b): undefined reference to `cuDeviceComputeCapability' deviceQueryDrv.cpp:(.text.startup+0x127): undefined reference to `cuDeviceGetName' deviceQueryDrv.cpp:(.text.startup+0x16a): undefined reference to `cuDriverGetVersion' deviceQueryDrv.cpp:(.text.startup+0x1f0): undefined reference to `cuDeviceTotalMem_v2' deviceQueryDrv.cpp:(.text.startup+0x262): undefined reference to `cuDeviceGetAttribute' deviceQueryDrv.cpp:(.text.startup+0x457): undefined reference to `cuDeviceGetAttribute' deviceQueryDrv.cpp:(.text.startup+0x4bc): undefined reference to `cuDeviceGetAttribute' deviceQueryDrv.cpp:(.text.startup+0x502): undefined reference to `cuDeviceGetAttribute' deviceQueryDrv.cpp:(.text.startup+0x533): undefined reference to `cuDeviceGetAttribute' obj/x86_64/release/deviceQueryDrv.cpp.o:deviceQueryDrv.cpp:(.text.startup+0x55e): more undefined references to `cuDeviceGetAttribute' follow collect2: ld returned 1 exit status make[2]: *** [../../bin/linux/release/deviceQueryDrv] Error 1 make[2]: Leaving directory `/home/john/NVIDIA_GPU_Computing_SDK/C/src/deviceQueryDrv' make[1]: *** [src/deviceQueryDrv/Makefile.ph_build] Error 2 make[1]: Leaving directory `/home/john/NVIDIA_GPU_Computing_SDK/C' make: *** [all] Error 2 I would appreciate any help that anyone can provide me with. If I can provide any further information please let me know. Thanks.

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  • Checking data of all same class elements

    - by Tiffani
    I need the code to check the data-name value of all instances of .account-select. Right now it just checks the first .account-select element and not any subsequent ones. The function right now is on click of an element such as John Smith, it checks the data-name of the .account-select lis. If the data-names are the same, it does not create a new li with the John Smith data. If no data-names are equal to John Smith, then it adds an li with John Smith. This is the JS-Fiddle I made for it so you can see what I am referring to: http://jsfiddle.net/rsxavior/vDCNy/22/ Any help would be greatly appreciated. This is the Jquery Code I am using right now. $('.account').click(function () { var acc = $(this).data("name"); var sel = $('.account-select').data("name"); if (acc === sel) { } else { $('.account-hidden-li').append('<li class="account-select" data-name="'+ $(this).data("name") +'">' + $(this).data("name") + '<a class="close bcn-close" data-dismiss="alert" href="#">&times;</a></li>'); } }); And the HTML: <ul> <li><a class="account" data-name="All" href="#">All</a></li> <li><a class="account" data-name="John Smith" href="#">John Smith</a></li> </ul> <ul class="account-hidden-li"> <ul>

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  • Pattern/Matcher in Java?

    - by user1007059
    I have a certain text in Java, and I want to use pattern and matcher to extract something from it. This is my program: public String getItemsByType(String text, String start, String end) { String patternHolder; StringBuffer itemLines = new StringBuffer(); patternHolder = start + ".*" + end; Pattern pattern = Pattern.compile(patternHolder); Matcher matcher = pattern.matcher(text); while (matcher.find()) { itemLines.append(text.substring(matcher.start(), matcher.end()) + "\n"); } return itemLines.toString(); } This code works fully WHEN the searched text is on the same line, for instance: String text = "My name is John and I am 18 years Old"; getItemsByType(text, "My", "John"); immediately grabs the text "My name is John" out of the text. However, when my text looks like this: String text = "My name\nis John\nand I'm\n18 years\nold"; getItemsByType(text, "My", "John"); It doesn't grab anything, since "My" and "John" are on different lines. How do I solve this?

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  • Parsing back to 'messy' API strcuture

    - by Eric Fail
    I'm fetching data from an online database (REDcap) via API and the data gets delivered in as comma separated string like this, RAW.API <- structure("id,event_arm,name,dob,pushed_text,pushed_calc,complete\n\"01\",\"event_1_arm_1\",\"John\",\"1979-05-01\",\"\",\"\",2\n\"01\",\"event_2_arm_1\",\"John\",\"2012-09-02\",\"abc\",\"123\",1\n\"01\",\"event_3_arm_1\",\"John\",\"2012-09-10\",\"\",\"\",2\n\"02\",\"event_1_arm_1\",\"Mary\",\"1951-09-10\",\"def\",\"456\",2\n\"02\",\"event_2_arm_1\",\"Mary\",\"1978-09-12\",\"\",\"\",2\n", "`Content-Type`" = structure(c("text/html", "utf-8"), .Names = c("", "charset"))) I have this script that nicely parses it into a data frame, (df <- read.table(file = textConnection(RAW.API), header = TRUE, sep = ",", na.strings = "", stringsAsFactors = FALSE)) id event_arm name dob pushed_text pushed_calc complete 1 1 event_1_arm_1 John 1979-05-01 <NA> NA 2 2 1 event_2_arm_1 John 2012-09-02 abc 123 1 3 1 event_3_arm_1 John 2012-09-10 <NA> NA 2 4 2 event_1_arm_1 Mary 1951-09-10 def 456 2 5 2 event_2_arm_1 Mary 1978-09-12 <NA> NA 2 I then do some calculations and write them to pushed_text and pushed_calc whereafter I need to format the data back to the messy comma separated structure it came in. I imagine something like this, API.back <- `some magic command`(df, ...) identical(RAW.API, API.back) [1] TRUE Some command that can format my data from the data frame I made, df, back to the structure that the raw API-object came in, RAW.API. Any help would be very appreciated.

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  • Enhanced REST Support in Oracle Service Bus 11gR1

    - by jeff.x.davies
    In a previous entry on REST and Oracle Service Bus (see http://blogs.oracle.com/jeffdavies/2009/06/restful_services_with_oracle_s_1.html) I encoded the REST query string really as part of the relative URL. For example, consider the following URI: http://localhost:7001/SimpleREST/Products/id=1234 Now, technically there is nothing wrong with this approach. However, it is generally more common to encode the search parameters into the query string. Take a look at the following URI that shows this principle http://localhost:7001/SimpleREST/Products?id=1234 At first blush this appears to be a trivial change. However, this approach is more intuitive, especially if you are passing in multiple parameters. For example: http://localhost:7001/SimpleREST/Products?cat=electronics&subcat=television&mfg=sony The above URI is obviously used to retrieve a list of televisions made by Sony. In prior versions of OSB (before 11gR1PS3), parsing the query string of a URI was more difficult than in the current release. In 11gR1PS3 it is now much easier to parse the query strings, which in turn makes developing REST services in OSB even easier. In this blog entry, we will re-implement the REST-ful Products services using query strings for passing parameter information. Lets begin with the implementation of the Products REST service. This service is implemented in the Products.proxy file of the project. Lets begin with the overall structure of the service, as shown in the following screenshot. This is a common pattern for REST services in the Oracle Service Bus. You implement different flows for each of the HTTP verbs that you want your service to support. Lets take a look at how the GET verb is implemented. This is the path that is taken of you were to point your browser to: http://localhost:7001/SimpleREST/Products/id=1234 There is an Assign action in the request pipeline that shows how to extract a query parameter. Here is the expression that is used to extract the id parameter: $inbound/ctx:transport/ctx:request/http:query-parameters/http:parameter[@name="id"]/@value The Assign action that stores the value into an OSB variable named id. Using this type of XPath statement you can query for any variables by name, without regard to their order in the parameter list. The Log statement is there simply to provided some debugging info in the OSB server console. The response pipeline contains a Replace action that constructs the response document for our rest service. Most of the response data is static, but the ID field that is returned is set based upon the query-parameter that was passed into the REST proxy. Testing the REST service with a browser is very simple. Just point it to the URL I showed you earlier. However, the browser is really only good for testing simple GET services. The OSB Test Console provides a much more robust environment for testing REST services, no matter which HTTP verb is used. Lets see how to use the Test Console to test this GET service. Open the OSB we console (http://localhost:7001/sbconsole) and log in as the administrator. Click on the Test Console icon (the little "bug") next to the Products proxy service in the SimpleREST project. This will bring up the Test Console browser window. Unlike SOAP services, we don't need to do much work in the request document because all of our request information will be encoded into the URI of the service itself. Belore the Request Document section of the Test Console is the Transport section. Expand that section and modify the query-parameters and http-method fields as shown in the next screenshot. By default, the query-parameters field will have the tags already defined. You just need to add a tag for each parameter you want to pass into the service. For out purposes with this particular call, you'd set the quer-parameters field as follows: <tp:parameter name="id" value="1234" /> </tp:query-parameters> Now you are ready to push the Execute button to see the results of the call. That covers the process for parsing query parameters using OSB. However, what if you have an OSB proxy service that needs to consume a REST-ful service? How do you tell OSB to pass the query parameters to the external service? In the sample code you will see a 2nd proxy service called CallREST. It invokes the Products proxy service in exactly the same way it would invoke any REST service. Our CallREST proxy service is defined as a SOAP service. This help to demonstrate OSBs ability to mediate between service consumers and service providers, decreasing the level of coupling between them. If you examine the message flow for the CallREST proxy service, you'll see that it uses an Operational branch to isolate processing logic for each operation that is defined by the SOAP service. We will focus on the getProductDetail branch, that calls the Products REST service using the HTTP GET verb. Expand the getProduct pipeline and the stage node that it contains. There is a single Assign statement that simply extracts the productID from the SOA request and stores it in a local OSB variable. Nothing suprising here. The real work (and the real learning) occurs in the Route node below the pipeline. The first thing to learn is that you need to use a route node when calling REST services, not a Service Callout or a Publish action. That's because only the Routing action has access to the $oubound variable, especially when invoking a business service. The Routing action contains 3 Insert actions. The first Insert action shows how to specify the HTTP verb as a GET. The second insert action simply inserts the XML node into the request. This element does not exist in the request by default, so we need to add it manually. Now that we have the element defined in our outbound request, we can fill it with the parameters that we want to send to the REST service. In the following screenshot you can see how we define the id parameter based on the productID value we extracted earlier from the SOAP request document. That expression will look for the parameter that has the name id and extract its value. That's all there is to it. You now know how to take full advantage of the query parameter parsing capability of the Oracle Service Bus 11gR1PS2. Download the sample source code here: rest2_sbconfig.jar Ubuntu and the OSB Test Console You will get an error when you try to use the Test Console with the Oracle Service Bus, using Ubuntu (or likely a number of other Linux distros also). The error (shown below) will state that the Test Console service is not running. The fix for this problem is quite simple. Open up the WebLogic Server administrator console (usually running at http://localhost:7001/console). In the Domain Structure window on the left side of the console, select the Servers entry under the Environment heading. The select the Admin Server entry in the main window of the console. By default, you should be viewing the Configuration tabe and the General sub tab in the main window. Look for the Listen Address field. By default it is blank, which means it is listening on all interfaces. For some reason Ubuntu doesn't like this. So enter a value like localhost or the specific IP address or DNS name for your server (usually its just localhost in development envirionments). Save your changes and restart the server. Your Test Console will now work correctly.

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  • A quiz with results

    - by Keon Davies
    I'm currently working on programming a quiz withe results. I've tried this: <html> <body> <h1></h1> <form> <ol> <li> How much are you willing to spend on a phone per month?</li> <ul> <li><input type = "radio" name = "q1" id="q1_1"> £5-£10.</input></li> <li><input type = "radio" name = "q1" id="q1_2"> £10-£15.</input></li> <li><input type = "radio" name = "q1" id="q1_3"> £15-£20.</input></li> <li><input type = "radio" name = "q1" id="q1_4"> £20-£25.</input></li> <li><input type = "radio" name = "q1" id="q1_5"> £25-£30.</input></li> <li><input type = "radio" name = "q1" id="q1_6"> £30-£35.</input></li> <li><input type = "radio" name = "q1" id="q1_7"> £35-£40.</input></li> </ul> <li> Are you good with technology</li> <ul> <li><input type = "radio" name = "q2" id="q2_1"> Yes.</input></li> <li><input type = "radio" name = "q2" id="q2_2"> No.</input></li> </ul> <li> Are you looking for an easy to use phone</li> <ul> <li><input type = "radio" name = "q3" id="q3_1"> Yes.</input></li> <li><input type = "radio" name = "q3" id="q3_2"> No.</input></li> </ul> <li> Are you looking for a modern type of phone?</li> <ul> <li><input type = "radio" name = "q4" id="q4_1"> Yes.</input></li> <li><input type = "radio" name = "q4" id="q4_2"> No.</input></li> </ul> <li> How big do you want the phone to be?</li> <ul> <li><input type = "radio" name = "q5" id="q5_1"> Big.</input></li> <li><input type = "radio" name = "q5" id="q5_2"> Medium.</input></li> <li><input type = "radio" name = "q5" id="q5_3"> Small.</input></li> <li><input type = "radio" name = "q5" id="q5_4"> I don't really mind.</input></li> </ul> <li> Do you care about the colour of the phone?</li> <ul> <li><input type = "radio" name = "q6" id="q6_1"> Yes.</input></li> <li><input type = "radio" name = "q6" id="q6_2"> No.</input></li> </ul> <li> Have you ever owned a phone before?</li> <ul> <li><input type = "radio" name = "q7" id="q7_1"> Yes.</input></li> <li><input type = "radio" name = "q7" id="q7_2"> No.</input></li> </ul> <li> Do you want to be able to use the phone to get out of awkward social situations?</li> <ul> <li><input type = "radio" name = "q8" id="q8_1"> Yes.</input></li> <li><input type = "radio" name = "q8" id="q8_2"> No.</input></li> </ul> <li> Do you want to be able to access the app store and download apps using your phone?</li> <ul> <li><input type = "radio" name = "q9" id="q9_1"> Yes.</input></li> <li><input type = "radio" name = "q9" id="q9_2"> No.</input></li> </ul> <li> What happened to the last phone you owned?</li> <ul> <li><input type = "radio" name = "q10" id="q10_1"> I got bored of it.</input></li> <li><input type = "radio" name = "q10" id="q10_2"> It broke.</input></li> <li><input type = "radio" name = "q10" id="q10_3"> The contract ran out.</input></li> <li><input type = "radio" name = "q10" id="q10_4"> Other.</input></li> </ul> </ol> <input type = "button" value = "Submit" onclick="getResults()"> <input type = "reset" value = "Clear"></input> <textarea id="result">The right phone for you will be displayed here.</textarea> </html> <script> function getResults() { if (document.getElementById('q1_1').checked && document.getElementById('q2_1').checked && document.getElementById('q3_1').checked && document.getElementById('q4_1').checked && document.getElementById('q5_1').checked && document.getElementById('q6_1').checked && document.getElementById('q7_1').checked && document.getElementById('q8_1').checked && document.getElementById('q9_1').checked && document.getElementById('q10_1').checked ) { document.getElementById('result').innerHTML = 'Unfortunately, the iPhone is the right phone for you.'; } } </script> </body> But it's just too long winded. Is there any other ways I can design a quiz like this but without having to write a block of code for each radio button?

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  • Why lock-free data structures just aren't lock-free enough

    - by Alex.Davies
    Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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  • Running Multiple WebLogic and OSB Domains

    - by jeff.x.davies
    I have any number of OSB domain created on my machine at any point in time. For example, I have different domains for different version of Oracle Service Bus and Oracle SOA Suite. I also have different domains for different purposes. I have a demo domain and another domain for the projects in my blog. Starting with OSB 11g and the Apache Derby server, there is a small "gotcha" if you want to create multiple domains on a devevelopment machine. When you create a new domain for OSB 11g it will use the same database info for all databases and this will cause an error when starting the admin server of the second domain (the first domain doesn't have to be running for this error to occur). Here is an example of the error message in the server console: ####<Mar 8, 2011 2:58:48 PM PST> <Critical> <JTA> <jeff-laptop> <AdminServer> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<WLS Kernel>> <> <> <1299625128464> <BEA-110482> <A logging last resource failed during initialization. The server cannot boot unless all configured logging last resources (LLRs) initialize. Failing reason: weblogic.transaction.loggingresource.LoggingResourceException: java.sql.SQLException: JDBC LLR, table verify failed for table 'WL_LLR_ADMINSERVER', row 'JDBC LLR Domain//Server' record had unexpected value 'osb11gR1PS3//AdminServer' expected 'OSBCIM//AdminServer'*** ONLY the original domain and server that creates an LLR table may access it *** The solution is to create a database instance for each of your domains and this is very simple to do. After you create a domain using the Configuration Wizard, locate the wlsbjmsrpDataSource-jdbc.xml file that is found under the DOMAIN_HOME/config/jdbc directory. Near the top of the file you will see the following entry: <url>jdbc:derby://localhost:1527/osbexamples;create=true;ServerName=localhost;databaseName=osbexamples</url> You need to modify this entry with a different and unique database name. The easiest way to do this is to substiture the name of your domain. For example: <url>jdbc:derby://localhost:1527/mydomain;create=true;ServerName=localhost;databaseName=mydomain</url> will create a database named mydomain . Now, when you restart the admin server for the domain, it will create the new database for you. Do this for each domain you create on your development machine and you'll have no troubles. The process is much simpler if you are creating a domain using the Configuration Wizard. Simply name the database when you get to the Configure JDBC Component Schema step of the Configuration Wizard, select the OSB JMS Reporting Provider and set the name in the DBMS/Service field to whatever name you like, as shown in Figure 1 below. Figure 1 – Configuring the JDBC Component Schema That is all there is to it. Now you can create as many domains on your leptop or development machine as you like and not have to worry about them conflicting with each other.

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  • Tidbits of goodness - Podcasts, REST, JSON

    - by jeff.x.davies
    I've been quiet for a while, busy with a variety of projects. I did want to let you all know about a couple of things going on. First, I have been participating in architectural podcasts with Bob Rhubart. If you are interested in hearing these short (about 10 minutes each) recordings where a group of us discuss enterprise architecture and its future, check out http://blogs.oracle.com/archbeat/2010/05/podcast_show_notes_evolving_en.html Next, I have been working on the public sample code for the Oracle Service Bus 11g release. I'm now expanding my samples to include SCA, BPEL and the Oracle Adapters. This is really great experience for me because I have been learning these other tools to a deeper level and this provides insight into developing better solutions. You know the old saying, "If the only tool you have is a hammer, you tend to appraoch every problem as if it were a nail." However, I'm not the only one working on these samples. We have alot of our best and brightest working on sample code for the 11g release. Take a look at https://soasamples.samplecode.oracle.com/ to see all of the samples for SOA Suite 11g A reader wrote to me and asked me about using OSB to return information in JSON format. I don't have a sample posted for this yet, but I am working on getting one packaged up. In the mean time I can tell you that it is dead simple to do in OSB. Use the instructions I gave in an earlier blog entry on creating REST services using OSB, specify Messaging Service as the service type that takes a Text message and returns a Text message. Then have the OSB proxy service return a JSON formatted string (by replacing the contents of the $body variable with the JSON text) and you're done! This approach allows you to use OSB services from within Javascript/AJAX seamlessly. As I get more samples posted to the OTN site, I'll let you know. I have lots of interesting stuff on the way.

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  • Why not to use StackTrace to find what method called you

    - by Alex.Davies
    Our obfuscator, SmartAssembly, does some pretty crazy reflection. It's an obfuscator, it's sort of its job to do things in the most awkward way possible. But sometimes, you can go too far. One such time is this little gem from the strings encoding feature: StackTrace stackTrace = new StackTrace(); StackFrame frame = stackTrace.GetFrame(1); Type ownerType = frame.GetMethod().DeclaringType; It's designed to find the type where the calling method is defined. A user found that strings encoding occasionally broke on x64 systems. Very strange. After some debugging (thank god for Reflector Pro, it would be impossible to debug processed assemblies without it) I found that the ownerType I got back was wrong. The reason is that the x64 JIT does tail call optimisation. This saves space on the stack, and speeds things up, by throwing away a method's stack frame if the last thing that it calls is the only thing returned. When this happens, the call to StackTrace faithfully tells you that the calling method is the one that called the one we really wanted. So using StackTrace isn't safe for anything other than debugging, and it will make your code fail in unpredictable ways. Don't use it!

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  • What do you call an obfuscator that isn't an obfuscator?

    - by Alex.Davies
    SmartAssembly, formerly {smartassembly}, version 5 is now available as an Early Access Build. You can get it here: http://www.red-gate.com/MessageBoard/viewforum.php?f=116 We're having second thoughts about the name change though. It isn't that we like the curly brackets, far from it. The trouble is that the first rule of product naming is to name a product by what it does. SmartAssembly may make an assembly smarter, but that's not something people really google for. The trouble is, I can't think of a better name for it. That's because SmartAssembly really does two completely separate things: Obfuscates Sets up your assembly for the awesome exception reports which get sent to you whenever your application crashes. You may have been (un?)lucky enough to see one in reflector if you use it. This is what those exception reports look like when they arrive back with the developer: Look at all those local variables! If you ask me, this is much cooler than the obfuscation. So obviously we don't want to call it just "Red Gate Obfuscator" or something, because it doesn't do justice to the exception reporting. What would you call it?

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  • Why lock statements don't scale

    - by Alex.Davies
    We are going to have to stop using lock statements one day. Just like we had to stop using goto statements. The problem is similar, they're pretty easy to follow in small programs, but code with locks isn't composable. That means that small pieces of program that work in isolation can't necessarily be put together and work together. Of course actors scale fine :) Why lock statements don't scale as software gets bigger Deadlocks. You have a program with lots of threads picking up lots of locks. You already know that if two of your threads both try to pick up a lock that the other already has, they will deadlock. Your program will come to a grinding halt, and there will be fire and brimstone. "Easy!" you say, "Just make sure all the threads pick up the locks in the same order." Yes, that works. But you've broken composability. Now, to add a new lock to your code, you have to consider all the other locks already in your code and check that they are taken in the right order. Algorithm buffs will have noticed this approach means it takes quadratic time to write a program. That's bad. Why lock statements don't scale as hardware gets bigger Memory bus contention There's another headache, one that most programmers don't usually need to think about, but is going to bite us in a big way in a few years. Locking needs exclusive use of the entire system's memory bus while taking out the lock. That's not too bad for a single or dual-core system, but already for quad-core systems it's a pretty large overhead. Have a look at this blog about the .NET 4 ThreadPool for some numbers and a weird analogy (see the author's comment). Not too bad yet, but I'm scared my 1000 core machine of the future is going to go slower than my machine today! I don't know the answer to this problem yet. Maybe some kind of per-core work queue system with hierarchical work stealing. Definitely hardware support. But what I do know is that using locks specifically prevents any solution to this. We should be abstracting our code away from the details of locks as soon as possible, so we can swap in whatever solution arrives when it does. NAct uses locks at the moment. But my advice is that you code using actors (which do scale well as software gets bigger). And when there's a better way of implementing actors that'll scale well as hardware gets bigger, only NAct needs to work out how to use it, and your program will go fast on it's own.

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  • A better way to do concurrent programming

    - by Alex.Davies
    Programming to take advantage of multicore processors is hard. If you let multiple threads access the same memory, bad things happen. To avoid this, you use the lock keyword, but if you use that in the wrong way, your code deadlocks. It's all a nightmare. Luckily, there's a better way - Actors. They're really easy to think about. They're really safe (if you follow a couple of simple rules). And high-performance, type-safe actors are now available for .NET by using this open-source library: http://code.google.com/p/n-act/ Have a look at the site for details. I'll blog with more reasons to use actors and tips and tricks to get the best parallelism from them soon.

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  • C# async and actors

    - by Alex.Davies
    If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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  • Automated Error Reporting in .NET Reflector - harnessing the most powerful test rig in existence

    - by Alex.Davies
    I know a testing system that will find more bugs than all the unit testing, integration testing, and QA you could possibly do. And the chances are you're not using it. It's called your users. It's a cliché that you should test so that you find your bugs rather than your users. Of course you should. But it's also a cliché that no software is ever shipped bug-free. Lost cause? No, opportunity! I think .NET Reflector 6 is pretty stable. In fact I know exactly how stable it is, because some (surprisingly high) proportion of its users tell me every time it crashes: If they press "Send Error Report", I get: And then I fix it. As a rough guess, while a standard stack trace is enough to fix a problem 30% of the time, having all those local variables in the stack trace means I can fix it about 80% of the time. How does this all happen? Did it take ages to code this swish system? Nope, it was one checkbox in SmartAssembly. It adds some clever code to your assembly to capture local variables every time an exception is thrown, and to ask your user to report it to you, with a variety of other useful information. Of course not all bugs show up as exceptions. But if you get used to knowing that SmartAssembly will tell you when an exception happens, you begin to change your coding style. Now, as long as an exception gets thrown in any situation you don't expect, you'll fix it if it ever happens. You'll start throwing exceptions liberally, and stop having to think about whether tiny edge cases are possible, as long as they throw an exception if they happen.

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  • Is it bad practice for services to share a database in SOA?

    - by Paul T Davies
    I have recently been reading Hohpe and Woolf's Enterprise Integration Patterns, some of Thomas Erl's books on SOA and watching various videos and podcasts by Udi Dahan et al. on CQRS and Event Driven systems. Systems in my place of work suffer from high coupling. Although each system theoretically has its own database, there is a lot of joining between them. In practice this means there is one huge database that all systems use. For example, there is one table of customer data. Much of what I've read seems to suggest denormalising data so that each system uses only its database, and any updates to one system are propagated to all the others using messaging. I thought this was one of the ways of enforcing the boundaries in SOA - each service should have its own database, but then I read this: http://stackoverflow.com/questions/4019902/soa-joining-data-across-multiple-services and it suggests this is the wrong thing to do. Segregating the databases does seem like a good way of decoupling systems, but now I'm a bit confused. Is this a good route to take? Is it ever recommended that you should segregate a database on, say an SOA service, an DDD Bounded context, an application, etc?

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  • What modern design pattern / software engineering books for Java SE 6 do you recommend ?

    - by Scott Davies
    Hi, I am very familiar with Java 6 SE language features and am now looking for modern books that cover design patterns in Java for beginners as well as software engineering books that discuss architectures, algorithms and best practices in Java coding (sort of like the Effective C# books). I am aware of the classic GoF design patterns book, however, I'd like a more modern reference that takes advantage of the features of Java 6 SE. What books would you recommend ? Thanks, Scott

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  • Accessing Repositories from Domain

    - by Paul T Davies
    Say we have a task logging system, when a task is logged, the user specifies a category and the task defaults to a status of 'Outstanding'. Assume in this instance that Category and Status have to be implemented as entities. Normally I would do this: Application Layer: public class TaskService { //... public void Add(Guid categoryId, string description) { var category = _categoryRepository.GetById(categoryId); var status = _statusRepository.GetById(Constants.Status.OutstandingId); var task = Task.Create(category, status, description); _taskRepository.Save(task); } } Entity: public class Task { //... public static void Create(Category category, Status status, string description) { return new Task { Category = category, Status = status, Description = descrtiption }; } } I do it like this because I am consistently told that entities should not access the repositories, but it would make much more sense to me if I did this: Entity: public class Task { //... public static void Create(Category category, string description) { return new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; } } The status repository is dependecy injected anyway, so there is no real dependency, and this feels more to me thike it is the domain that is making thedecision that a task defaults to outstanding. The previous version feels like it is the application layeer making that decision. Any why are repository contracts often in the domain if this should not be a posibility? Here is a more extreme example, here the domain decides urgency: Entity: public class Task { //... public static void Create(Category category, string description) { var task = new Task { Category = category, Status = _statusRepository.GetById(Constants.Status.OutstandingId), Description = descrtiption }; if(someCondition) { if(someValue > anotherValue) { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.UrgentId); } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.SemiUrgentId); } } else { task.Urgency = _urgencyRepository.GetById (Constants.Urgency.NotId); } return task; } } There is no way you would want to pass in all possible versions of Urgency, and no way you would want to calculate this business logic in the application layer, so surely this would be the most appropriate way? So is this a valid reason to access repositories from the domain?

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  • .NET Demon support for VS 11 dark theme

    - by Alex.Davies
    I'm pleased to announce that .NET Demon will be shipping simultaneously with Visual Studio 11, whenever it ends up being released. That means we're going to make sure that a version of .NET Demon is released very near to the Visual Studio 11 final release which supports the new version of VS fully. The interesting part of this support is going to be the new dark theme of VS, which I'm looking forward to using. I'm told dark colours reduce eye strain for developers. It's important that extensions like .NET Demon switch to a dark theme when the rest of the IDE changes, or the dark theme will look silly. Unfortunately, none of my favourite extensions look right in the dark theme yet, so even though I use Visual Studio 11 beta for my day-to-day development already, I can't use the dark theme. Luckily .NET Demon uses WPF throughout, and the team at Microsoft are helping us to use the WPF Style system to make it easy for me to implement the support without having to add colour attributes to all the controls manually. We should have dark theme support in .NET Demon in the next month or so.

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  • OSB and Ubuntu 10.04 - Too Many Open Files

    - by jeff.x.davies
    When installing the latest Oracle Service Bus (11gR1PS3) onto my Ubuntu 10.04 system, the Eclipse IDE was complaining about there being too many open files. The Oracle Service Bus and the Oracle Enterprise Pack for Eclipse (aka OEPE) do make use of ALOT of files. By default, Ubuntu will restrict each user to 1024 open files. A much more realistic number for OSB development is 4096. Changing the file limit in Ubuntu is fairly simple (if arcane). You will need to modify two different files and then restart your server. First, you need to modify the limits.conf file as the root user. Open a terminal window and enter the following command: sudo gedit /etc/security/limits.conf Add the following 2 lines to the file. The asterisk simply means that the rule will apply to all users. * soft nofile 4096 * hard nofile 4096 Save your changes and close gedit. The second file to change is the common-session file. Use the following command: sudo gedit /etc/pam.d/common-session Add the following line: session required pam_limits.so Save the file and exit gedit. Restart your machine. You shouldn't have any more problems with too many open files anymore.

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  • Would a multitouch capable PC allow me to do Android development simulating the touch UI without an Android device ?

    - by Scott Davies
    Hi, I recently purchased a Samsung Galaxy Tab as a reference implementation (phone and first gen Android tablet), of Android 2.x for app development. I have noticed a slew of Android 3.0 slates being talked about at CES 2011 (Motorola XOOM, etc.). If I had a multitouch PC with the Android SDK/Emulator on it, would this allow me to more closely approximate device simulation by allowing user input via the multitouch screen ? Would it work via touch just like Windows 7 recognizes touch as mouse style input ? Has anyone done this ? Thanks, Scott

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  • AsyncBridge? Async on .NET 4.0 using VS11

    - by Alex.Davies
    I've just found something quite cool. It's a code snippet that lets you use the real VS 11 C#5 compiler to write code that uses the async and await keywords, but to target .NET 4.0. It was published by Daniel Grunwald (from SharpDevelop).That means I can stop using the Async CTP for VS2010, which is not at all supported anymore, and a pain to install if you have windows updates turned on. Obviously I couldn't ask all my users to install .NET 4.5 beta, but .NET Demon is a VS 2010 extension, so we already have .NET 4.0. At the time of writing, VS11 is in beta still, but hopefully it's stable enough for my team to use!I would have written the code myself, but I had the wrong impression that the C# 5 beta compiler only looked in mscorlib for the helper classes it needs to implement async methods. Turns out you can provide them yourself. You can get the code here: https://gist.github.com/1961087You just add it to your project, and the compiler will apparently pick it up and use it to implement async/await. I'm at my parents' place for Easter without access to a machine with VS 11 to try it out. Let me know whether you get it to work!This reminds me of LINQBridge, which let us use C# 3 LINQ, but only require .NET 2. We should stick up a webpage to explain, with a nice easy dll, put it in nuget, and call it AsyncBridge.If you were really enthusiastic, you could re-implement the skeleton of the Task Parallel Library against .NET 2 to use async/await without even requiring .NET 4. Our usage stats suggest that practically everyone that uses Red Gate tools already has .NET 4 installed though, so I don't think I'll go to the effort.

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  • A new tool in beta: Conflict Alert

    - by Alex Davies
    You know that manual merges are a real pain? Well, I’ve just released a Visual Studio extension that makes manual merges a thing of the past. No source control system can automatically merge two edits to the same line of code. Conflict Alert solves this by warning you that you are heading down a path that will cause a manual merge later down the line. You choose whether you want to carry on, or talk to your teammate and find out what they are doing. Have you ever warned your teammates that you are doing a big refactor, and that they should ‘keep out of class X’? Conflict Alert tells them for you automatically by highlighting the sections of code that you have edited.   It doesn’t need to connect to your source control system, so it works no matter which you use. Its a first release, and I hope it is useful. Any feedback would be gratefully received. Grab a teammate and try it now.

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