If broken it is, fix it you should

Using the powers of the debugger to solve the problems of the world - and a bag of chips    by Tess Ferrandez, ASP.NET Escalation Engineer (Microsoft)

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  • Blog Post: Reader email: Need help troubleshooting perf/memory issues

    I get several emails every day (through the blog) with urgent requests to help troubleshoot memory issues or memory related performance issues. Some just say “we have a memory issue, how do I troubleshoot it?” and others are far far more detailed with links to dumps and everything:) I...
  • Blog Post: Debugging a classic ReaderWriterLock deadlock with SOSex.dll

    I was helping out on an issue the other day where the process would stall if they added enough users in their load tests.  Btw, serious kudos to them for making load tests, so much nicer to work with a problem in test rather than when it is getting critical on a production machine. We gathered some...
  • Blog Post: High CPU in .NET app using a static Generic.Dictionary

    A couple of weeks ago I helped out on a high CPU issue in an ASP.NET application. Problem description Every so often they started seeing very slow response times and in some cases the app didn’t respond at all and at the same time the w3wp.exe process was sitting at very high CPU usage 80-90%. ...
  • Blog Post: .NET Hang Case study: The danger of locking on strings

    I had an interesting case today where an asp.net app was stuck in a true deadlock. In other words two threads were both waiting for resources that the other thread owned. The scenario in these cases usually goes something like this: FunctionA (locks on ResourceA) and calls FunctionB where it...
  • Blog Post: ASP.NET Case Study: Hang when loading assemblies

    The other day I came across an issue where an ASP.NET site stopped responding and didn’t start serving requests again until the W3WP.exe process was restarted. We grabbed some memory dumps with debug diag before restarting the process to see what was going on. Debugging the dumps: I opened the...
  • Blog Post: First step in troubleshooting complex issues: Define and scope your issue properly

    Is it a plane, is it a bird, is it a UFO? Before you can delve into any kind of troubleshooting of an issue you need to thoroughly define it.  If you don’t you’ll probably end up spending a lot of time randomly gathering and looking at data that is probably not even relevant to the issue at hand...
  • Blog Post: A case of lost session variables when using out of process session state

    Recently I had a case where the customer had an issue with session variables.  The claim was that if they use in-proc session state their session variables would work just fine, but if they changed the session mode to stateserver in web.config their sessions were lost. <sessionState mode="StateServer"...
  • Blog Post: First look at debugging .NET 4.0 dumps in Visual Studio 2010

    I know that for a lot of you this is a bit far into the future, but I thought it would be nice to run through a few of my lab scenarios to show off some of the new features in Visual Studio 2010.  I am sure that I will miss a bunch of cool features here as this post is just based on my first experience...
  • Blog Post: Neat .NET 2.0 StackViewer to troubleshoot hangs/performance issues

    Bret wrote a post about Managed Stack Explorer , a really nice tool that was developed in 2006 but since then seems to have been forgotten. It’s excellent if you want to troubleshoot hangs/performance issues in a process but don’t want to go through the hassle of getting and analyzing a dump.  ...
  • Blog Post: Developers are from Mars, Ops people are from Venus… or It looked good on paper

    A few weeks back me and Micke (one of our Architect Evangelists) had a session at TechDays where we talked about “things that looked good on paper” i.e. things that sound pretty ok in the design/development phase but sometimes turn out to be a disaster in production. We are both pretty passionate about...
  • Blog Post: .NET Hang: Analyzing Debug Diag output

    Earlier this week I got an email from a reader who had a hang in an application and sent in some Debug Diag logs. In order for me to dig in deeper I would need to open a support case as I would have to ask follow up questions and look at the dumps etc. However, I wanted to show some interesting details...
  • Blog Post: .NET Hang: My application hangs after I called my WCF service a couple of times

    I know it is a little late, but Happy New Year to all of you. My holiday break was great, and I wish I would have had some more time to blog, but instead I got an XBOX 360 and a Guitar Hero World Tour game so the blog had to take the back seat for a while… My whole family and even my mom are now hooked...
  • Blog Post: Video of my TechEd presentation of Common Issues in ASP.NET and how to debug them with Windbg

    My TechEd presentation “Common Issues in ASP.NET and how to debug them with Windbg” is now up on channel 9, so if you want to watch it, here you go http://channel9.msdn.com/posts/MSDNSweden/Vanliga-fel-som-grs-med-ASPNET-och-hur-du-hittar-dem-med-WinDbg/ Have fun, Tess
  • Blog Post: Slides for interactive TechEd Sessions about debugging .net issues in windbg

    ... and here are the slides for the interactive session
  • Blog Post: Slides and resources for TechED presentations about debugging .NET issues with Windbg

    I still have to figure out a way to host the video from the break-out session but until then, here are the slides for my presentations (attached). And here are a list of some of the tools and resources I used for the presentations Tool/Resource Comment Download Link Debugging...
  • Blog Post: Performance by Design – PDC 2008

    Rico Mariani (Chief Architect of Visual Studio – previously performance architect for .net), Vance Morrison (Performance architect for .net) and Mark Friedman (Architect Lead for the Developer Division of Performance Engineering) had a full day talk at the PDC about performance. Unfortunately recordings...
  • Blog Post: Using VSTS Test and Profilers to troubleshoot a High CPU in GC issue

    Following my post about how to troubleshoot a low CPU performance issue with VSTS Test, I will now do the same for lab 4 where we have high CPU in GC. The scenario is pretty similar in that we have a page ( http://localhost/BuggyBits/AllProducts.aspx ) that seems to be taking a lot of time to execute...
  • Blog Post: Using VSTS Test and Profilers to troubleshoot performance issues (low cpu hang)

    I’ve been wanting to dig into the Test features in Visual Studio Team System for a while to “debug” issues during the test phase. In my previous post I linked to a Swedish screen cast by Mikael Deurell, but for those of you who don’t know Swedish I thought I’d walk through troubleshooting a couple of...
  • Blog Post: Q&A Reader emails about .NET memory leaks and random questions

    Here are of some of the reader emails I got this week and my answers to them... How do I troubleshoot this memory leak Debugging techniques for capturing stacks of OOMS Do you have a list of Debugging 101 links? Debugging managed code in IE Getting to dependency properties with sos let me know if this...
  • Blog Post: OutOfMemoryExceptions while remoting very large datasets

    When you have to pass an object back and forth between processes or application domains you have to serialize it into some type of stream that can be understood by both the client and the server.   The more complex and big the object gets the more expensive it is to serialize, both CPU wise...
  • Blog Post: Troubleshooting a performance issue with Failed Request Tracing and appcmd in IIS7

    I know I'm a little late in the game, but I decided that after vacation it was finally time for me to install Windows 2008 on my Vista box and play around with some of the IIS 7 features like Failed Request Tracing (known as FRT or FREB) and the appcmd tool. I wanted to show you an alternative way...
  • Blog Post: 100% CPU in vbc.exe when compiling large vb.net web applications in Microsoft Visual Studio 2008

    We just released a hotfix for an issue where you get 100% CPU in vbc.exe when compiling large applications in Microsoft Visual Studio 2008. Apart from the 100% CPU situation you may also notice symptoms like visual studio taking a very long time to return or error messages like Error 246 Timed...
  • Blog Post: ASP.NET Case Study: Deadlock waiting in GetToSTA

    This is an issue I come across once in a while and since I am not a COM expert by any means I actually had to check in with our COM guys to see what was going on in this case, and as it turned out (this is embarrassing:)) I had already written about the root cause of this issue before ( here ). So what...
  • Blog Post: CLR Inside Out: Large Object Heap Uncovered

    In many of my posts I have discussed performance issues and memory issues caused by excessive use of the Large Object Heap, here are a few examples... ASP.NET Case Study: High CPU in GC - Large objects and high allocation rates ASP.NET Case Study: Bad perf, high memory usage and high CPU in GC - Death...
  • Blog Post: The 21 most popular blog posts

    I started this blog 2.5 years ago today, mostly because I felt that the same types of issues came up over and over and over in our support cases. I figured that if I started writing about them, a lot of people would be able to resolve them on their own, or even better avoid them in the first place. A...
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