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vmware player won't run on CentOS due to missing /dev/vmmon, what could be the problem?

- by Graphics Noob

So I've tried installing vmware player 3.1.4 and 3.1.3 and both times had the same problem, when I try to load a VM I get the error "Could not open /dev/vmmon". When I ls /dev/ I can see there is no "vmmon" device present. When I try running: sudo /etc/init.d/vmware start I get the output: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [FAILED] which shows that the Virtual Machine Monitor fails to load. I tried following the advice on this site and ran vmware-modconfig --console --install-all I notice during the compilation there are no errors, but at the end I get the message: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [ OK ] Unable to start services Out of curiousity I tried: sudo /sbin/insmod /lib/modules/2.6.18-238.9.1.el5xen/misc/vmmod.ko But got the error message: insmod: error inserting 'vmmon.ko': -1 Invalid module format I have a feeling this may be the root of the problem, but I don't know what could be causing it or how to fix it.

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Sendmail slow to accept emails

- by Rich

I have a PHP web app which is using SMTP to sendmail on localhost to send email. I would like sendmail to accept the mail request immediately and queue it for later sending, as I don't want to have user-facing request threads blocked on emails. Sendmail is installed with the default settings on RHEL web servers. Sometimes sendmail is blocking for a long time after the MAIL command is sent -- sometimes taking 60 or 90 seconds to accept the mail. The time take is usually very close to 60 or 90 sec, which makes me think this is some kind of timeout. I have looked in the sendmail logs, and there are plenty of "deferred" emails, but nothing which looks responsible for this delay. How can I diagnose what is slowing down sendmail? How can I configure sendmail to always accept the mail immediately and to queue the mail for later sending? Update: I'm not sure, but it looks like this might be linked to aol.com addresses. I strongly suspect that sendmail is doing some kind of blocking receipient address verification at the accept-email-for-sending stage. How can I disable that, so that sendmail doesn't block my UI threads? Update 2: This only seems to happen at busy times. Perhaps I am running out of sendmail threads or something? How can I check that?

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wso2 ESB: server configuration CRITICAL

- by nuvio

My Scenario: I have server_1 (192.168.10.1) with wso2-ESB and server_2 (192.168.10.2) with Glassfish-v3 + web services. Problem: I am trying to create a proxy in ESB using the java Web Services, but the created proxy does not respond properly. The log says: Unable to sendViaPost for http or https does not change the result. I think I should configure the axis2.xml but I am having trouble, and don't know what to do. What is the configuration for my scenario? Please help me! EDIT: To be clear, I can directly consume the WebService in the Glassfish server, it works normal, both port and url are accessible. Only when I create a "Pass through Proxy" in the ESB, it does not work. I don't think is matter of Proxy configuration...I never had problems while deployed locally, problems started once I have uploaded the ESB to a remote server. I really would need someone to point me what is the correct procedure when installing the ESB on a remote host: configuration of axis2.xml and carbon.xml, ports, transport receivers etc... P.S. I had a look at the official (wso2 esb and carbon) guides with no luck, but I am missing something... Endpoint of Java Web Service: http://192.168.10.2:8080/HelloWorld/Hello?wsdl ESB Proxy Enpoint: http://192.168.10.1:8280/services/HelloProxy The following is my axis2.xml configuration, please check it: <transportReceiver name="http" class="org.apache.synapse.transport.nhttp.HttpCoreNIOListener"> <parameter name="port" locked="false">8280</parameter> <parameter name="non-blocking" locked="false">true</parameter> <parameter name="bind-address" locked="false">192.168.10.1</parameter> <parameter name="WSDLEPRPrefix" locked="false">https//192.168.10.1:8280</parameter> <parameter name="httpGetProcessor" locked="false">org.wso2.carbon.transport.nhttp.api.NHttpGetProcessor</parameter>  </transportReceiver>  <transportReceiver name="https" class="org.apache.synapse.transport.nhttp.HttpCoreNIOSSLListener"> <parameter name="port" locked="false">8243</parameter> <parameter name="non-blocking" locked="false">true</parameter> <parameter name="bind-address" locked="false">192.168.10.1</parameter> <parameter name="WSDLEPRPrefix" locked="false">https://192.168.10.1:8243</parameter>  <parameter name="httpGetProcessor" locked="false">org.wso2.carbon.transport.nhttp.api.NHttpGetProcessor</parameter> <parameter name="keystore" locked="false"> <KeyStore> <Location>repository/resources/security/wso2carbon.jks</Location> <Type>JKS</Type> <Password>wso2carbon</Password> <KeyPassword>wso2carbon</KeyPassword> </KeyStore> </parameter> <parameter name="truststore" locked="false"> <TrustStore> <Location>repository/resources/security/client-truststore.jks</Location> <Type>JKS</Type> <Password>wso2carbon</Password> </TrustStore> </parameter>  </transportReceiver>

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trying to use mod_proxy with httpd and tomcat

- by techsjs2012

I been trying to use mod_proxy with httpd and tomcat... I have on VirtualBox running Scientific Linux which has httpd and tomcat 6 on it.. I made two nodes of tomcat6. I followed this guide like 10 times and still cant get the 2nd node of tomcat working.. http://www.richardnichols.net/2010/08/5-minute-guide-clustering-apache-tomcat/ Here is the lines from my http.conf file <Proxy balancer://testcluster stickysession=JSESSIONID> BalancerMember ajp://127.0.0.1:8009 min=10 max=100 route=node1 loadfactor=1 BalancerMember ajp://127.0.0.1:8109 min=10 max=100 route=node2 loadfactor=1 </Proxy> ProxyPass /examples balancer://testcluster/examples <Location /balancer-manager> SetHandler balancer-manager AuthType Basic AuthName "Balancer Manager" AuthUserFile "/etc/httpd/conf/.htpasswd" Require valid-user </Location> Now here is my server.xml from node1 <?xml version='1.0' encoding='utf-8'?>   <Server port="8005" shutdown="SHUTDOWN">  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />  <Listener className="org.apache.catalina.core.JasperListener" />  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" /> <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />  <GlobalNamingResources>  <Resource name="UserDatabase" auth="Container" type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved" factory="org.apache.catalina.users.MemoryUserDatabaseFactory" pathname="conf/tomcat-users.xml" /> </GlobalNamingResources>  <Service name="Catalina">         <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />   <Engine name="Catalina" defaultHost="localhost" jvmRoute="node1">      <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>  <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true" xmlValidation="false" xmlNamespaceAware="false">     </Host> </Engine> </Service> </Server> now here is the server.xml file from node2 <?xml version='1.0' encoding='utf-8'?>   <Server port="8105" shutdown="SHUTDOWN">  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />  <Listener className="org.apache.catalina.core.JasperListener" />  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" /> <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />  <GlobalNamingResources>  <Resource name="UserDatabase" auth="Container" type="org.apache.catalina.UserDatabase" description="User database that can be updated and saved" factory="org.apache.catalina.users.MemoryUserDatabaseFactory" pathname="conf/tomcat-users.xml" /> </GlobalNamingResources>  <Service name="Catalina">         <Connector port="8109" protocol="AJP/1.3" redirectPort="8443" />   <Engine name="Catalina" defaultHost="localhost" jvmRoute="node2">      <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>  <Host name="localhost" appBase="webapps" unpackWARs="true" autoDeploy="true" xmlValidation="false" xmlNamespaceAware="false">     </Host> </Engine> </Service> </Server> I dont know what it is. but I been trying for days

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Parallelism in .NET – Part 19, TaskContinuationOptions

- by Reed

My introduction to Task continuations demonstrates continuations on the Task class. In addition, I’ve shown how continuations allow handling of multiple tasks in a clean, concise manner. Continuations can also be used to handle exceptional situations using a clean, simple syntax. In addition to standard Task continuations , the Task class provides some options for filtering continuations automatically. This is handled via the TaskContinationOptions enumeration, which provides hints to the TaskScheduler that it should only continue based on the operation of the antecedent task. This is especially useful when dealing with exceptions. For example, we can extend the sample from our earlier continuation discussion to include support for handling exceptions thrown by the Factorize method: // Get a copy of the UI-thread task scheduler up front to use later var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Start our task var factorize = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); // When we succeed, report the results to the UI factorize.ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), CancellationToken.None, TaskContinuationOptions.NotOnFaulted, uiScheduler); // When we have an exception, report it factorize.ContinueWith(task => textBox1.Text = string.Format("Error: {0}", task.Exception.Message), CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, uiScheduler); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The above code works by using a combination of features. First, we schedule our task, the same way as in the previous example. However, in this case, we use a different overload of Task.ContinueWith which allows us to specify both a specific TaskScheduler (in order to have your continuation run on the UI’s synchronization context) as well as a TaskContinuationOption. In the first continuation, we tell the continuation that we only want it to run when there was not an exception by specifying TaskContinuationOptions.NotOnFaulted. When our factorize task completes successfully, this continuation will automatically run on the UI thread, and provide the appropriate feedback. However, if the factorize task has an exception – for example, if the Factorize method throws an exception due to an improper input value, the second continuation will run. This occurs due to the specification of TaskContinuationOptions.OnlyOnFaulted in the options. In this case, we’ll report the error received to the user. We can use TaskContinuationOptions to filter our continuations by whether or not an exception occurred and whether or not a task was cancelled. This allows us to handle many situations, and is especially useful when trying to maintain a valid application state without ever blocking the user interface. The same concepts can be extended even further, and allow you to chain together many tasks based on the success of the previous ones. Continuations can even be used to create a state machine with full error handling, all without blocking the user interface thread.

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asynchrony is viral

- by Daniel Moth

It is becoming hard to write code today without introducing some form of asynchrony and, if you are using .NET (e.g. for Windows Phone 8 or Windows Store apps), that means sooner or later you have to await something and mark your method as async. My most recent examples included introducing speech recognition in my Translator By Moth phone app where I had to await mySpeechRecognizerUI.RecognizeWithUIAsync() and when moving that code base to a Windows Store project just to show a MessageBox I had to await myMessageDialog.ShowAsync(). Any time you need to invoke an asynchronous method in your code, you have a choice to make: kick off the operation but don’t wait for it to complete (otherwise known as fire-and-forget), synchronously wait for it to complete (which will entail blocking, which can be bad, especially on a UI thread), or asynchronously wait for it to complete before continuing on with the rest of the method’s work. In most cases, you want the latter, and the await keyword makes that trivial to implement. When you use the magical await keyword in front of an API call, then you typically have to make additional changes to your code: This await usage is within a method of course, and now you have to annotate that method with async. Furthermore, you have to change the return type of the method you just annotated so it returns a Task (if it previously returned void), or Task<myOldReturnType> (if it previously returned myOldReturnType). Note that if it returns void, in some cases you could cheat and stop there. Furthermore, any method that called this method you just annotated with async will now also be invoking an asynchronous operation, so you have to make that change in the body of the caller method to introduce the await keyword before the call to the method. …you guessed it, you now have to change this caller method to be annotated with async and have its return types tweaked... …and it goes on virally… At some point you reach the root of your user code, e.g. a GUI event handler, and whoever calls that void method can already deal with the fact that you marked it as async and the viral introduction of the keywords stops there… This is all wonderful progress and a very powerful mechanism, and I just wish someone had written a refactoring tool to take care of this… anyone? I mentioned earlier that you have a choice when invoking an asynchronous operation. If the first time you encounter this you wish to localize the impact of all these changes and essentially try to turn the asynchronous behavior into synchronous by blocking - don't! For reasons why you don't want to do that, read Toub's excellent blog post (and check out the rest of his blog with gems on async programming starting with the Async FAQ). Just embrace the pattern knowing that when you use one instance of an await, you'll propagate the change all the way to the root user code method, e.g. typically an event handler. Related aside: I just finished re-writing my MessageBox wrapper class for Phone projects, including making it work in Windows Store projects, and it does expect you to use it with an await :-). I'll share that in an upcoming post for those of you that have the same need… Comments about this post by Daniel Moth welcome at the original blog.

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C# 5 Async, Part 2: Asynchrony Today

- by Reed

The .NET Framework has always supported asynchronous operations. However, different mechanisms for supporting exist throughout the framework. While there are at least three separate asynchronous patterns used through the framework, only the latest is directly usable with the new Visual Studio Async CTP. Before delving into details on the new features, I will talk about existing asynchronous code, and demonstrate how to adapt it for use with the new pattern. The first asynchronous pattern used in the .NET framework was the Asynchronous Programming Model (APM). This pattern was based around callbacks. A method is used to start the operation. It typically is named as BeginSomeOperation. This method is passed a callback defined as an AsyncCallback, and returns an object that implements IAsyncResult. Later, the IAsyncResult is used in a call to a method named EndSomeOperation, which blocks until completion and returns the value normally directly returned from the synchronous version of the operation. Often, the EndSomeOperation call would be called from the callback function passed, which allows you to write code that never blocks. While this pattern works perfectly to prevent blocking, it can make quite confusing code, and be difficult to implement. For example, the sample code provided for FileStream’s BeginRead/EndRead methods is not simple to understand. In addition, implementing your own asynchronous methods requires creating an entire class just to implement the IAsyncResult. Given the complexity of the APM, other options have been introduced in later versions of the framework. The next major pattern introduced was the Event-based Asynchronous Pattern (EAP). This provides a simpler pattern for asynchronous operations. It works by providing a method typically named SomeOperationAsync, which signals its completion via an event typically named SomeOperationCompleted. The EAP provides a simpler model for asynchronous programming. It is much easier to understand and use, and far simpler to implement. Instead of requiring a custom class and callbacks, the standard event mechanism in C# is used directly. For example, the WebClient class uses this extensively. A method is used, such as DownloadDataAsync, and the results are returned via the DownloadDataCompleted event. While the EAP is far simpler to understand and use than the APM, it is still not ideal. By separating your code into method calls and event handlers, the logic of your program gets more complex. It also typically loses the ability to block until the result is received, which is often useful. Blocking often requires writing the code to block by hand, which is error prone and adds complexity. As a result, .NET 4 introduced a third major pattern for asynchronous programming. The Task<T> class introduced a new, simpler concept for asynchrony. Task and Task<T> effectively represent an operation that will complete at some point in the future. This is a perfect model for thinking about asynchronous code, and is the preferred model for all new code going forward. Task and Task<T> provide all of the advantages of both the APM and the EAP models – you have the ability to block on results (via Task.Wait() or Task<T>.Result), and you can stay completely asynchronous via the use of Task Continuations. In addition, the Task class provides a new model for task composition and error and cancelation handling. This is a far superior option to the previous asynchronous patterns. The Visual Studio Async CTP extends the Task based asynchronous model, allowing it to be used in a much simpler manner. However, it requires the use of Task and Task<T> for all operations.

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Asynchronous HTTP Client for Java

- by helifreak

As a relative newbie in the Java world, I am finding many things frustratingly obtuse to accomplish that are relatively trivial in many other frameworks. A primary example is a simple solution for asynchronous http requests. Seeing as one doesn't seem to already exist, what is the best approach? Creating my own threads using a blocking type lib like httpclient or the built-in java http stuff, or should I use the newer non-blocking io java stuff - it seems particularly complex for something which should be simple. What I am looking for is something easy to use from a developer point of view - something similar to URLLoader in AS3 - where you simply create a URLRequest - attach a bunch of event handlers to handle the completion, errors, progress, etc, and call a method to fire it off. If you are not familiar with URLLoader in AS3, its so super easy and looks something like this: private void getURL(String url) { URLLoader loader = new URLLoader(); loader.addEventListener(Event.Complete, completeHandler); loader.addEventListener(HTTPStatusEvent.HTTP_STATUS, httpStatusHandler); loader.addEventListener(IOErrorEvent.IO_ERROR, ioErrorHandler); URLRequest request = new URLRequest(url); // fire it off - this is asynchronous so we handle // completion with event handlers loader.load(request); } private void completeHandler(Event event) { URLLoader loader = (URLLoader)event.target; Object results = loader.data; // process results } private void httpStatusHandler(Event event) { // check status code } private void ioErrorHandler(Event event) { // handle errors }

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Threading 101: What is a Dispatcher?

- by Water Cooler v2

Once upon a time, I remembered this stuff by heart. Over time, my understanding has diluted and I mean to refresh it. As I recall, any so called single threaded application has two threads: a) the primary thread that has a pointer to the main or DllMain entry points; and b) For applications that have some UI, a UI thread, a.k.a the secondary thread, on which the WndProc runs, i.e. the thread that executes the WndProc that recieves messages that Windows posts to it. In short, the thread that executes the Windows message loop. For UI apps, the primary thread is in a blocking state waiting for messages from Windows. When it recieves them, it queues them up and dispatches them to the message loop (WndProc) and the UI thread gets kick started. As per my understanding, the primary thread, which is in a blocking state, is this: C++ while(getmessage(/* args &msg, etc. */)) { translatemessage(&msg, 0, 0); dispatchmessage(&msg, 0, 0); } C# or VB.NET WinForms apps: Application.Run( new System.Windows.Forms() ); Is this what they call the Dispatcher? My questions are: a) Is my above understanding correct? b) What in the name of hell is the Dispatcher? c) Point me to a resource where I can get a better understanding of threads from a Windows/Win32 perspective and then tie it up with high level languages like C#. Petzold is sparing in his discussion on the subject in his epic work. Although I believe I have it somewhat right, a confirmation will be relieving.

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python: nonblocking subprocess, check stdout

- by Will Cavanagh

Ok so the problem I'm trying to solve is this: I need to run a program with some flags set, check on its progress and report back to a server. So I need my script to avoid blocking while the program executes, but I also need to be able to read the output. Unfortunately, I don't think any of the methods available from Popen will read the output without blocking. I tried the following, which is a bit hack-y (are we allowed to read and write to the same file from two different objects?) import time import subprocess from subprocess import * with open("stdout.txt", "wb") as outf: with open("stderr.txt", "wb") as errf: command = ['Path\\To\\Program.exe', 'para', 'met', 'ers'] p = subprocess.Popen(command, stdout=outf, stderr=errf) isdone = False while not isdone : with open("stdout.txt", "rb") as readoutf: #this feels wrong for line in readoutf: print(line) print("waiting...\\r\\n") if(p.poll() != None) : done = True time.sleep(1) output = p.communicate()[0] print(output) Unfortunately, Popen doesn't seem to write to my file until after the command terminates. Does anyone know of a way to do this? I'm not dedicated to using python, but I do need to send POST requests to a server in the same script, so python seemed like an easier choice than, say, shell scripting. Thanks! Will

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Debugging an unresponsive iPhone UI

- by buggles

I have an application that needs to update its display every minute or so. To achieve this I was using performSelector:withObject:afterDelay, calling the selector that most of the time just changes some text in a label based on a very simple (and quick) calculation. [self performSelector:@selector(updateDisplay) withObject:nil afterDelay:60]; Occasionally during an update, I have to go off and get some data from the web, and so I do that in another thread using detachNewThreadSelector. That all worked and the "performSelector after Delay" call completes in a tiny fraction of a second, and only runs once a minute. Despite this, and despite running fine on the simulator, the single button in the app is largely unresponsive, not responding to multiple stabs. So, I had assumed peformSelector:afterDelay would not block, but I'm now wondering if it is blocking in some way? I even tried NOT doing the web-look-up incase this was somehow still impacting the responsiveness. No joy. [NSThread detachNewThreadSelector:@selector(updateFromURL) toTarget:self withObject:nil]; I then pushed it through shark to see if I could see anything obvious. From here I can see the web-lookup is the only thing taking any time, but it is only being done every couple of minutes, and then clearly not running on the main thread. The app itself is consuming a tiny fraction of 1% of the CPU (0.0000034%) over 20 minutes, so it just must be a blocking issue. So, am I missing something about performSelector:afterDelay? What other common newbie mistakes might I be making. If it helps, although I've been developing applications for over 20 years, the previous 10 have been largely Java. Perhaps I have a Java assumption loaded :-) Essentially I have assumed the main thread is like the EDT (only do UI stuff on it, but keep everything else off it).

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Could Python's logging SMTP Handler be freezing my thread for 2 minutes?

- by Oddthinking

A rather confusing sequence of events happened, according to my log-file, and I am about to put a lot of the blame on the Python logger, which is a bold claim. I thought I should get some second opinions about whether what I am saying could be true. I am trying to explain why there is are several large gaps in my log file (around two minutes at a time) during stressful periods for my application when it is missing deadlines. I am using Python's logging module on a remote server, and have set-up, with a configuration file, for all logs of severity of ERROR or higher to be emailed to me. Typically, only one error will be sent at a time, but during periods of sustained problems, I might get a dozen in a minute - annoying, but nothing that should stress SMTP. I believe that, after a short spurt of such messages, the Python logging system (or perhaps the SMTP system it is sitting on) is encountering errors or congestion. The call to Python's log is then BLOCKING for two minutes, causing my thread to miss its deadlines. (I was smart enough to move the logging until after the critical path of the application - so I don't care if logging takes me a few seconds, but two minutes is far too long.) This seems like a rather awkward architecture (for both a logging system that can freeze up, and for an SMTP system (Ubuntu, sendmail) that cannot handle dozens of emails in a minute**), so this surprises me, but it exactly fits the symptoms. Has anyone had any experience with this? Can anyone describe how to stop it from blocking? ** EDIT: I actually counted. A little under 4000 short emails in two hours. So far more than I suggested, sorry. But enough to over-fill a Sendmail's buffers?

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Linux time sample based profiler.

- by Caspin

short version: Is there a good time based sampling profiler for Linux? long version: I generally use OProfile to optimize my applications. I recently found a shortcoming that has me wondering. The problem was a tight loop spawning c++filt to demangle a c++ name. I only stumbled upon the code by accident while chasing down another bottleneck. The OProfile didn't show anything unusual about the code so I almost ignored it but my code sense told me to optimize the call and see what happened. I changed the popen of c++filt to abi::__cxa_demangle. The runtime went from more than a minute to a little over a second. About a x60 speed up. Is there a way I could have configured OProfile to flag the popen call? As the profile data sits now OProfile thinks the bottle neck was the heap and std::string calls (which BTW once optimized dropped the runtime to less than a second, more than x2 speed up). Here is my OProfile configuration: $ sudo opcontrol --status Daemon not running Event 0: CPU_CLK_UNHALTED:90000:0:1:1 Separate options: library vmlinux file: none Image filter: /path/to/excutable Call-graph depth: 7 Buffer size: 65536 Is there another profiler for Linux that could have found the bottleneck? I suspect the issue is that OProfile only logs its samples to the currently running process. I'd like it to always log its samples to the process I'm profiling. So if the process is currently switched out (blocking on IO or a popen call) OProfile would just place its sample at the blocked call. If I can't fix this, OProfile will only be useful when the executable is pushing near 100% CPU. It can't help with executables that that have inefficient blocking calls.

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Sending files using Winsock - optimal send() data length?

- by Meta

I am using Winsock with non-blocking sockets to send a file to a client. The way I'm doing it right now is that I read a chunk of 8192 bytes from the file, and then loop until all of it successfully goes through send() (obviously handling WSAEWOULDBLOCK as it occurs). I then move on and read the next 8192 bytes, and so on... Although I can use any other number than 8192 when I test the transfer on my local machine, once I try it over a network, it seems like 8191 is the largest number I can use. When I try to use any number higher than 8191 (starting with 8192), the file transfer becomes extremely slow (about 5 times slower). Is there any reason why 8191 is so special? I've done some more testing and it turns out that using 8000 is slightly faster (by 0.5%). If you understand why 8191 is so special, can you tell me if there is a number better than the others (better than 8000)? I have a feeling that it has something to do with the fact that the default send buffer allocated to the socket by Winsock is 8KB, but I don't understand why. It might also have something to do with the Nagle algorithm, but again, I'm not sure how. Note that I have not modified the SO_SNDBUF option nor the TCP_NODELAY option. Or am I doing this all wrong? What's the best way of sending a file over a non-blocking socket?

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Block facebook from my website

- by Joseph Szymborski

I have a secure link direction service I'm running (expiringlinks.co). If I change the headers in php to redirect my visitors, then facebook is able to show a preview of the website I'm redirecting to when users send links to one another via facebook. I wish to avoid this. Right now, I'm using an AJAX call to get the URL and javascript to redirect, but it's causing problems for users who don't use javascript. Here are a number of ways I'd like to block facebook, but I can't seem to get working: I've tried blocking the facebook bot (facebookexternalhit/1.0 and facebookexternalhit/1.1) but it's not working, I don't think they're using them for this functionality. I'm thinking of blocking the facebook IP addresses, but I can't find all of them, and I don't think it'll work unless I get all of them. I've thought of using a CAPTCHA or even a button, but I can't bring myself to do that to my visitors. Not to mention I don't think anyone would use the site. I've searched the facebook docs for meta tags that would "opt-me out", but haven't found one, and doubt that I would trust it if I had. Any creative ideas or any idea how to implement the ones above? Thank you so much in advance!

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Browser window popups - risks and special features

- by Sandeepan Nath

1. What exactly is the security risk with popups? The new browsers provide settings to block window popups (on blocking, sites with active popups display a message to user). What exactly is the security risk with popups? If allowing popups can execute something dangerous, then the main window can too. Is it not the case. I think I don't know about some special powers of window popups. 2. Any special features of popup windows? Take for example the HDFC bank netbanking site. The entire netbanking session happens in a new window popup and a user neither manually edit the URL or paste the URL in the main browser window. it does not work. Is a popup window needed for this feature? Does it improve security? (Asking because everything that is there in this site revolves around security - so they must have done that for a reason too). Why otherwise they would implement the entire netbanking on a popup window? 3. Is it possible to override browser's popup blocking settings Lastly, the HDFC site succcessfully displays popup window even when in the browser settings popups are blocked. So, how do they do it? Is that a browser hack? To see this - go to http://hdfcbank.com/ Under the "Login to your account" section select "HDFC Bank NetBanking" and click the "Login" button. You can verify that even if popups are blocked/popup blocker is enabled in the browser settings, this site is able to display popups. The answers to this question say that it is not possible to display popup windows if it has been blocked in browser settings. Solved Concluded with Pointy's solution and comments under that. Here is a fiddle demonstrating the same.

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Listening socket

- by hoodoos

I got a strange problem, I never actually expirienced this before, here is the code of the server (client is firefox in this case), the way I create it: _Socket = new Socket( AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp ); _Socket.Bind( new IPEndPoint( Settings.IP, Settings.Port ) ); _Socket.Listen( 1000 ); _Socket.Blocking = false; the way i accept connection: while( _IsWorking ) { if( listener.Socket.Poll( -1, SelectMode.SelectRead ) ) { Socket clientSocket = listener.Socket.Accept(); clientSocket.Blocking = false; clientSocket.SetSocketOption( SocketOptionLevel.Tcp, SocketOptionName.NoDelay, true ); } } So I'm expecting it hang on listener.Socket.Poll till new connection comes, but after first one comes it hangs on poll forever. I tried to poll it constantly with smaller delay, let's say 10 microseconds, then it never goes in SelectMode.SelectRead. I guess it maybe somehow related on client's socket reuse? Maybe I don't shutdown client socket propertly and client(firefox) decides to use an old socket? I disconnect client socket this way: Context.Socket.Shutdown( SocketShutdown.Both ); // context is just a wrapper around socket Context.Socket.Close(); What may cause that problem?

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JavaFX MouseEvent continues when I remove the object it happened on

- by Kyle

It took me a while to realize what was going on with mouse events going through my blocking dialog boxes when I closed them, but I finally figured out why. I still don't know any good way to fix it. I have a custom dialog box (that blocks the mouse) with a close button. When I click the close button, I remove the dialog box from the scene, but JavaFx is still processing the MouseEvent and now it finds that there is nothing blocking the screen behind where the cancel button was, so that component receives a MouseEvent. How do I make the mouseEvent stop processing when I see that they pressed cancel and remove the dialog box? Or, is there a way to make the removing of the dialog box not happen until after it is done processing the MouseEvent? Example Code for the problem: import javafx.stage.Stage; import javafx.scene.Scene; import javafx.scene.shape.Rectangle; import javafx.scene.input.MouseEvent; import javafx.scene.control.Button; var theScene:Scene; var btn:Button; Stage { title: "Application title" scene: theScene= Scene { width: 500 height: 200 content: [ Rectangle{ width: bind theScene.width height: bind theScene.height onMouseClicked: function(e:MouseEvent):Void{ println("Rectangle");} }, Button{ layoutX: 20 layoutY: 50 blocksMouse: true text: "JustPrint" action:function():Void{ println("JustPrint");} }, btn = Button{ layoutX: 20 layoutY: 20 blocksMouse: true text: "Cancel" action:function():Void{ println("Cancel"); delete btn from theScene.content;} }, ] } } When you press "JustPrint" you get: JustPrint When you press "Cancel" you get: Cancel Rectangle

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Why is post() not updating the DOM after it returns? Wierd timing problem observed.

- by Sephrial

Hi all, I have the following code that is really bugging me, I'm thinking perhaps the post() function needs to be blocking. I am new to jQuery(latest version) and AJAX, but I'm using ColdFusion which returns some HTML in the data variable. var dataResult; var statusResult; $.post('fh_result.cfm',$('#myform').serialize(),function(data,status){ dataResult = data; statusResult = status; }); //alert(statusResult); if ('success' == statusResult) { alert(statusResult); $('#result').html(dataResult); } When I uncomment out the first alert, it returns 'undefined' but then it goes into the if block and the next alert box it says 'success'. If I comment out that line it doesn't make it into the if statement at all. My guess is that I want to make this a blocking call or something because I want to insert the data on the page after the post. I also have a problem when I re-write the top code as follows: var dataResult; var statusResult; $.post('fh_result.cfm',$('#myform').serialize(),function(data,status){ dataResult = data; statusResult = status; alert(statusResult); $('#result').html(dataResult); }); //alert(statusResult); Now in this case, the alert says 'success' when I comment out the second alert box. When I uncomment it out, I get one alert that says success and the other that says undefined, but this time it updates the DOM with the result of the postback as desired. How can I do this without the alert box?

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Show menu when view is long pressed

- by swift1691

I've been looking around on the internet regarding my question but I couldn't find a straight answer. Is it possible to create a non-blocking menu similar to the overflow menu found in Android 4.0+ when a view is long pressed? I have a number of LinearLayout instances which have an OnLongClickListener which brings up a context menu, but it's not exactly what I am looking for. I was hoping for a smoother menu which is brought up when one of these instances is clicked, and removed when the user clicks outside of the menu's region. This is very similar to the way the overflow menu behaves in the Android ActionBar. So to sum up, is it possible to replicate the look-and-fell and the behavior of the overflow menu when using context menus? Here's hoping I don't have to jump through hoops to get the implementation that I desire. Thanks in advance. EDIT: After some digging I've found the PopupMenu which is exactly what I was looking for however it works only on devices running Honeycomb and above. Does anyone know of a way with which I can replicate this menu behavior in older versions of Android without using blocking windows like dialogs?

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Java Socket - how to catch Exception of BufferedReader.readline()

- by Hasan Tahsin

I have a Thread (let's say T1) which reads data from socket: public void run() { while (running) { try { BufferedReader reader = new BufferedReader( new InputStreamReader(socket.getInputStream()) ); String input = reader.readLine(); } catch (IOException e) { e.printStackTrace(); } } } Another Thread (lets say T2) try to finish the program in one of its method. Therefore T2 does the following: T1.running = false; socket.close(); Here is this scenario for which i couldn't find a solution: T1 is active and waiting for some input to read i.e. blocking. context switching T2 is active and sets running to false, closes the socket context switching because T1 was blocking and T2 closed the socket, T1 throws an Exception. What i want is to catch this SocketException. i can't put a try/catch(SocketException) in T1.run(). So how can i catch it in T1's running-method? If it's not possible to catch it in T1's running, then how can i catch it elsewhere? PS: "Another question about the Thread Debugging" Normally when i debug the code step by step, i lose the 'active running line' on a context switch. Let's say i'm in line 20 of T1, context switch happens, let's assume the program continues from the 30.line of T2, but the debugger does not go/show to the 30.line of T2, instead the 'active running line' vanishes. So i lose the control over the code. I use Eclipse for Java and Visual Studio for C#. So what is the best way to track the code while debugging on a context switch ?

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'The RPC server is unavailable' when converting a physical ISA/Forefront TMG machine to virtual (P2V) in SCVMM

- by Goran B.

When I try to convert a physical ISA/TMG machine to virtual using SCVMM, i keep getting an error in the Collect machine configuration step ('Scan Now' button): VMM is unable to complete the request. The connection to the agent MACHINE_NAME was lost. Ensure that the computer MACHINE_NAME exists on the network, WMI service and the agent are installed and running and that a firewall is not blocking HTTP and WMI traffic. ID: 3157 Details: The RPC server is unavailable (0x800706BA) Firewall rules allow for RPC traffic from the SCVMM machine to ISA/TMG machine.

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ISA Server 2006 SP1 :: Allow unauthenticated users (non domain users) access to external (internet)

- by Klaptrap

Now that we have applied an internal to external rule blocking all users access to the internet, other than those users in a whitelist, we have the obvious issue of non authenticated users, not on our domain, i.e.; domain-less guests not being able to access the internet. Other than configuring each machine to use our alternative gateway - which would require a member of IT to be onsite everytime a guest arrives - can this be done through ISA adn AD?

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Bugmenot (registration bypasser) alternative that doesn't suck?

- by davr

I used to love Bugmenot...but then they started blocking more and more sites. Now I'd say a good 75% of the time I try to find logins on bugmenot, the site is blocked. Is there a service like bugmenot that doesn't block sites? EDIT: For example, all of these sites require registration to download files, and all of them are blocked from BugMeNot. To be clear, this problem is because BugMeNot stops users from adding logins for them, not because of the individual sites themselves: dcemu.co.uk, ubuntuforums.org, club.cdfreaks.com

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ISA Server 2006 SP1 :: Allow unauthenticated users (non domain users) access to external (internet)

- by Klaptrap

Now that we have applied an internal to external rule blocking all users access to the internet, other than those users in a whitelist, we have the obvious issue of non authenticated users, not on our domain, i.e.; domain-less guests not being able to access the internet. Other than configuring each machine to use our alternative gateway - which would require a member of IT to be onsite everytime a guest arrives - can this be done through ISA adn AD?

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