Fortunately there is a nice feature included in debugdiag that lets it perform an automatic analysis. Debugging finding a native heap leak with windbg debug things. Using windbg to find memory leaks in silverlight applications posted by sergey barskiy on 6 september 2010, 6. I am not going to try to duplicate that information here. I got this dump file by using the create dump file in the task manager. Weve updated windbg to have more modern visuals, faster windows, a fullfledged scripting experience, with the easily extensible debugger data model front and center. Windows debugging techniques debugging memory leaks. Run your application in ie and get it to a stage where you think the memory leak is occuring.
So the first thing i do is to publish the application and then run it in ie. In previous post silverlight debugging with visual studio, i demonstrated that visual studio is a powerful and the most convenient tool for debugging managed applications. Feb 11, 2009 when should you use a memory leak detector. Glavs blog debugging silverlight apps using windbg. Tools to narrow down and know which process is consuming memory abnormally how to use debug diag to debug memory leak. The sos extension and windbg is a really nice team so working without them can be tough. Sep 06, 2010 in light of recent issues with memory leaks in silverlight and the fact that service pack that was supposed to address these issues was released last week, i found myself working on an application, trying to confirm that it does not leak any longer. Programs written in languages that have garbage collection, such as managed code, might also need memory debuggers, e. It might be tough sometimes, but its a good brainteasing practice and its a good way to learn how inner things work. I then discovered the very handy windbg tool that comes as part of the debugging tools for windows download. The kernel debugger determines the precise location of a kernelmode memory leak.
To simplify my approach, i created a destructor for my view with the following code. Debugging managed code memory leak with memory dump using. As most of the people doing xaml development already know silverlight 4 shipped at mix 10 this year. Feb 05, 2012 recently, ive spent a couple of days seeking and fixing memory leaks in our silverlight application. Things get worst if the code is not written by you, or if the code base is quite huge. Using windbg to find memory leaks in silverlight applications. You have a silverlight for windows embedded application in windows embedded compact 20. How to clear the memory of radwindow in silverlight and how to avoid the memory leak in silverlight application. Mar 12, 2009 what if you dont know the source of the memory leak in the first place. Use the following techniques to determine the cause of a usermode memory leak. Debugging silverlight applications and detecting memory leaks is a daunting task that one must do when writing any nontrivial application using silverlight. Feb 21, 2008 troubleshooting the native heap is a bit harder. Using the kernel debugger to find a kernelmode memory leak. Creating memory dump is easy and you can analyze it offline as long as you want 3.
Even if you have the luxury, it might not be as easy as you think. One of the most common problems with native code is memory leaks, the major reason being that memory management is left to the application itself. The memory leak detector i wrote is meant for use in those cases where you have the feeling one of the objects you wrote isnt being collected when it should be by the gc. Net, there are still situations when this is not happening. How do i use a dump file to diagnose a memory leak. Using driver verifier to find a kernelmode memory leak. After this we only have one memory leak lab to go before you have gone through the whole lab set.
Memory leak refers to a gradual loss of memory space due to memory blocks not being released when they are no longer needed. The section enabling postmortem debugging in the windbg documentation discusses this well. Previous demos and setup instructions if you are new to the debugging labs, here you can find information on how to set up the labs as well as links to the previous labs in the series. Wpf and silverlight allow you to define your user interface and bind it to data with a minimum of code, meaning that you can also introduce memory leaks into your application without even realizing it. Hunting memory leaks in silverlight mikhail shilkov. The first technique determines which process is leaking memory. Run the silverlight application and bring it to a state where you think a memory problem. Detecting memory leaks in silverlight applications using. I dont think i can get a clue from inside of vs when connected via remote debugging. Final answer unfortunately, with the information given, its not possible to tell the exact reason. Memory leak debugging with windbg without user stack trace.
This technique reveals the pool tag associated with the memory leak. Debugging a memory leak in silverlight 4 the grayzone. Aug 17, 2009 hi all, this post is a continuation of managed debugging with windbg. In this exercise we shall discuss some of the fundamental steps in memory leak detection. I used a trial version of redgate profiling software to look for the memory leak, but the memory leak is somewhere in the unmanaged code.
I am trying to use windbg to look at memory leaks in a silverlight application. See this blog post for more detailsnet visualstudio2010 memory leaks crashdumps memory profiling. The trick behind this memory leak detector is the usage of the weakreference class. But, as i plow through some books and bad code examples i introduce all kinds of bugs. If this value doesnt grow but virtual bytes do, the memory leak is in the unmanaged world.
To set windbg as the default managed debugger, youd need to set these. Memory leaks in silverlight applications may be found with windbg tool. It could be possible with the help of old memory, e. First you need to download and install the debugging tools for windows, after this is done go through the following procedure to find and fix the memory. Memory leak in a silverlight for windows embedded app in. Event handlers that are not properly disposed keep a strong reference to the objects and by this prevent the gc to free the memory. Purpose introduction to windbg and kernel debugging the two machines you need two windows machines to do this project. Debugging managed code memory leak with memory dump using windbg.
Windbg is part of the debugging tools for windows package. I wrote a simple silverlight program and i found that the memory was on the increase when i ceaselessly clicked the add button and delete button alternately. I have a full memory dump but in this instance i dont have a user stack trace database to go with it, i have up to date symbols and the original binaries that go with the dump, normally, ive been able to use the. Windows debugging techniques debugging memory leaks perfmon part 5. It works fine on pc, but on mac it has a huge memory leak. Additionally, the memory leak may cause the application to crash. Usually you dont have luxury to attach debugger to the running process on the server.
Tech support scams are an industrywide issue where scammers trick you into paying for unnecessary technical support services. Jun 28, 2011 even if you have the luxury, it might not be as easy as you think. At any rate, our silverlight apps, after opening certain pages many times 8, the application would crash. This official release contained a lot of issues memory leaks included and it was a reasonable decision for microsoft to postpone their gdr general distribution release the one that comes with windows update version. I have installed both 32 and 64 bit windbg i cant recall where i read that for silverlight apps i should use the 32 bit. Though there are tools available in the market that will help you in memory leak detection, most of these tools are not free. Nov 10, 2010 using this it becomes a lot easier to find, and fix, your memory leak. This article describes some windbg commands that can be used on daily basis. Net could do a garbage collection, find out that there are 120 mb free and use that instead of asking for 110 mb of new memory. Silverlight application memory leaks detector codeproject. But for some advanced debugging scenarios, like memory leak, deadlock, runaway processthread, kernel debugging, and advanced remotecrashui debugging etc, windbg or cdb, ntsd, kd is usually.
Jul, 2009 to confirm that multiple instances of the user control were still in memory, i resorted to using windbg. Although gc is doing most of the job in reclaiming the memory from unneeded objects in. Debugging finding a native heap leak with windbg debug. Right now im trying to analyzing the dump file of iexplorer. Net wont use the nt heap, but saves some virtual memory for its own heap. Windbg is powerful, relatively lightweight and free.
The attach option in windbg is available under the file menu, or can be launched using the f6 shortcut. While working on a silverlight application for my current engagement, we were seeing some weird memory issues and application crashes. You can use the memory leak detector to monitor this behavior. To confirm that multiple instances of the user control were still in memory, i resorted to using windbg. Debugging memory leak is a musthave skill for most server side app developers especially when you move to cloud. For more information about the weakreference class, visit here. Hunting down memory leaks in silverlight vishful thinking. Debugging finding a native heap leak with windbg 09 jan 2015 tweet. This sets the registry key hklm\software\microsoft\windows nt\currentversion\aedebug to windbg. Silverlight 4 memory leaks, telerik controls and a solution. To troubleshoot silverlight applications with windbg and sos you would take a memory dump of the iexplore. Using performance monitor to find a usermode memory leak. These are some of the important performance counters we can check with performance monitor when having memory issues with. Oct 07, 2015 windbg and memory leak detection there are many tools available in the market that will help you in memory leak detection, most of these tools are not free and take too much of cpu and memory and effectively hard to work on with large systems.
I know that miguel will also be publishing some debugging tips around silverlight and he is a silverlight gun so keep an eye on his blog for more details. Windows debugging techniques debugging memory leaks crt apis background. Net udf plugin i had to break away from my daily use of. Feb 23, 2012 i used a trial version of redgate profiling software to look for the memory leak, but the memory leak is somewhere in the unmanaged code. Memory leaks to watch out for in wpf and silverlight. Once we have configured windbg for the symbol file path, start the process which is leaking memory, and attach windbg to it. Taking memory dumps i need some advice on reading them.
Debug silverlight 5 app process dump file with windbg. First you need to download and install the debugging tools for windows, after this is done go through the following procedure to find and fix the memory leak. Silverlight application memory leaks detector in ui for. One is the target machine, which is a virtual machine running win xp sp3. In summary, the below are reasons for using windbg to debug managed code memory leak with memory dump. This is usually the best way to get information from a native leak.
Display help text that describes the extension commands exported from extensiondll or from the extension dll at the top of the chain. The new visual studio 20 ultimate can now natively diagnose memory issues using dump files. Download debugging tools for windows windbg windows. Net memory leak thursday, march 12, 2009 in my last post, i explained how it was possible for hidden event handlers to introduce memory leaks and showed an easy way to prevent such leaks. Knowing how something is leaking is the first step to fixing it, and the web has some great resources for learning more about tracking down managed memory leaks in wpf and silverlight applications. A good solution to this problem which many developers are using is getting memory dump for the process in which you suspect there is memory leak and then debugging it with windbg. Aug 21, 2008 if you have hangs, performance, memory issues, exceptions or crashes in silverlight applications you can debug them using windbg and sos just like you would if the issues occurred in other. Using this it becomes a lot easier to find, and fix, your memory leak. Recently, ive spent a couple of days seeking and fixing memory leaks in our silverlight application. Previous demos and setup instructions if you are new to the debugging labs, here you can.
You can help protect yourself from scammers by verifying that the contact is a microsoft agent or microsoft employee and that the phone number is an official microsoft global customer service number. Walkthrough troubleshooting a native memory leak speaking. If you do not know which kernelmode driver or component is responsible for the leak, you should use the poolmon technique first. How to use the silverlight application memory leak detector.
Tools to narrow down and know which process is consuming memory abnormally how to. I opened it up in windbg and ran the following commandeeheap gc. Debugging silverlight applications with windbg and sos. Nov 17, 20 this article describes some windbg commands that can be used on daily basis. Following the steps below, you can confirm and debug memory leaks in silverlight and also in the. Ive written a silverlight app that works as an uploader for amazons s3. In summary, the below are reasons for using windbg to debug managed code memory leak with memory. Dec 19, 2008 but for some advanced debugging scenarios, like memory leak, deadlock, runaway processthread, kernel debugging, and advanced remotecrashui debugging etc, windbg or cdb, ntsd, kd is usually preferred, if not the only option. In short, you can set windbg as the default jit debugger by running windbg i. It is needed for server side applications and especially cloud applications 2. You can do so with either adplus as shown in my lab series or with debug diag, just remember that the process should be iexplore. These are due to bugs related to the allocation and deallocation of dynamic memory. I have done a bit with win32 com before but not enough to know all of the ins and outs.
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