[Valgrind-users] 答复: [Help] Valgrind sometime run the program very slowly sometimes , it last at least one hour. can you show me why or some way to analyze it?

[Wuweijia <wuw...@hu...>]

Hi
     Thanks for your advise.  You mean I need to download valgrind 3.13. and merge your commit, compile it.
      And Is there any api that I can dump the call stack of  the threads.
      I want  to add it to the code to show me more information to debug the program.

BR
Owen

-----邮件原件-----
发件人: Ivo Raisr [mailto:iv...@iv...] 
发送时间: 2018年1月23日 17:43
收件人: Wuweijia <wuw...@hu...>
抄送: val...@li...; Fanbohao <fan...@hu...>
主题: Re: [Valgrind-users] [Help] Valgrind sometime run the program very slowly sometimes , it last at least one hour. can you show me why or some way to analyze it?

2018-01-23 4:02 GMT+01:00 Wuweijia <wuw...@hu...>:
> Hi
>
>             I ran the program with mem-check,  99%  is okay, it will 
> not last long. But sometimes it last very long, at least one hour in 
> one function. And then I add the –trace-signals=yes to find what it happen.
> Valgrind show me some signal happened. Is there something related to 
> the time that the mem-check last too long. Or can you show me some 
> ways to analyze why the mem-check run too long sometimes.

Perhaps you will find useful a simple progress reporting facility recently integrated into Valgrind repo by Julian.
https://bugs.kde.org/show_bug.cgi?id=384633
Remark: you need to build Valgrind from the latest source as per http://valgrind.org/downloads/repository.html


Excerpt from the documentation:
---------------------------------------------
A new command line flag, --progress-interval=number, causes Valgrind to print a 1-line summary of progress every |number| seconds.
For example, when starting Firefox with --progress-interval=10, I get lines like this:

--32411-- PROGRESS: U 110s, W 113s, 97.3% CPU, EvC 414.79M, TIn 616.7k, TOut 0.5k, #thr 67
--32411-- PROGRESS: U 120s, W 124s, 96.8% CPU, EvC 505.27M, TIn 636.6k, TOut 3.0k, #thr 64
--32411-- PROGRESS: U 130s, W 134s, 97.0% CPU, EvC 574.90M, TIn 657.5k, TOut 3.0k, #thr 63
--32411-- PROGRESS: U 140s, W 144s, 97.2% CPU, EvC 636.34M, TIn 659.9k, TOut 3.0k, #thr 62
--32411-- PROGRESS: U 150s, W 155s, 96.8% CPU, EvC 710.21M, TIn 664.0k, TOut 17.7k, #thr 61
--32411-- PROGRESS: U 160s, W 201s, 79.6% CPU, EvC 822.38M, TIn 669.9k, TOut 75.8k, #thr 60

Each line shows:
   U:    total user time
   W:    total wallclock time
   CPU:  overall average cpu use
   EvC:  number of event checks.  An event check is a backwards branch
         in the simulated program, so this is a measure of forward progress
         of the program
   TIn:  number of code blocks instrumented by the JIT
   TOut: number of instrumented code blocks that have been thrown away
   #thr: number of threads in the program

From the progress of these, it is possible to observe:

* when the program is compute bound (TIn rises slowly, EvC rises rapidly)
* when the program is in a spinloop (TIn/TOut fixed, EvC rises rapidly)
* when the program is JIT-bound (TIn rises rapidly)
* when the program is rapidly discarding code (TOut rises rapidly)
* when the program is about to achieve some expected state (EvC arrives
  at some value you expect)
* when the program is idling (U rises more slowly than W)

I.