Apparent deadlock when running in Sampling mode

Code profiling for .NET developers.

Apparent deadlock when running in Sampling mode

Postby swythan » Mon May 13, 2013 12:16 pm

I'm trying to profile my app on and I can't get it to work in Sampling mode. Every time I try, my application appears to deadlock once it hits the code that I'm actually trying to profile. That is: CPU usage goes 0% and the program stops making progress.

The code I'm trying to use is using a lot of Parallel.For loops and Tasks, and I'm running on a system with 2x Intel Xeon E5-2665 CPUs, for a total of 32 logical cores (16 physical w/ hyper-threading). WinDbg shows that I have 61 .Net threads at the point of deadlock, with quite a few of them at :
Code: Select all

Any ideas? I'm happy to poke around some more with WinDbg, if that helps.


P.S. Line & Method-level timings work OK, but the CPU usage pattern I get is quite different from when I'm running without the profiler, so that's no good to me. I really need to get sampling-based profiling working. VS2012's sampling mode works, but that doesn't easily give me the "what method is running when" info that ANTS does.
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Postby james.billings » Tue May 14, 2013 1:16 pm

Thanks for your post- is it possible for you to supply the memory dump to us for analysis?

If it zips up pretty small, please email it to along with "F0072862" in the subject line. If it's still pretty large then I can set up some FTP space if you have nowhere else for it to go... feel free to email us with the above ref. in any case.
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I am seeing the same thing in

Postby seanhalliday » Wed Oct 09, 2013 3:58 pm

Application regularly hangs when in sampling mode and ANTS profiling just flatlines with "Blocked" as the only info when I select regions of the timeline.
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Experiencing the same issue

Postby cesar.fernandes » Mon Oct 14, 2013 1:28 pm

I am having the same issue reported at this thread. I am seeing exactly the same behaviour as seanhalliday.

Is there any solution for it? I haven't tried the other profiling methods, do they work?

Thanks in advance
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I am seeing the same thing in

Postby seanhalliday » Tue Oct 15, 2013 5:22 pm

@cesar.fernandes - I have not seen this issue with other profiling methods.
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Postby jessica.ramos » Wed Oct 16, 2013 5:10 pm

Hi seanhalliday and cesar.fernandes,

So sorry to hear you've run into this issue!

Could you each drop us a line at so we can open up tickets for you both and investigate this deadlock problem?

Ideally, we'd like to get a copies of your applications and/or hang dump files to really understand what's going wrong.

Jessica Ramos
Technical Support
Red Gate Software Ltd.
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Postby Chris.Allen » Thu Oct 17, 2013 5:46 pm

Curiously- this is an access denied exception from:

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