Re: missing Java method information in operf profile

[Maynard J. <may...@us...>]

On 08/25/2014 01:01 PM, Brian Hall wrote:
> I'm running the operf from AT 7.0-5 on a POWER8 system:
>   # /opt/at7.0/bin/operf -v
>   /opt/at7.0/bin/operf: oprofile 1.0.0git compiled on Jul 24 2014 13:49:08
> using the command (as root):
>   /opt/at7.0/bin/operf --events PM_RUN_CYC:10290000 --separate-thread --separate-cpu --system-wide
> 
> There are 14 active JVM processes running on the system that I am trying to profile.  For some reason, the profiles only contain full JIT compiler method information for 2 or 3 of the processes (it varies across different runs).  I have checked that the agentlib option is being correctly passed to the JVMs, and that the JIT dump files for all 14 processes are available in /tmp/.oprofile/jitdump at the time that operf is run.
> 
> A casual look at verbose output from operf didn't indicate any problems in accessing the JIT dump files, it just didn't try to process all of them.  I tried adding --lazy-conversion to the operf options, and that run did show an issue at the end of the verbose output:
>   add sym: name=Ljava/utilchild received signal 9
Hi, Brian,
This sounds similar to a problem that was reported on this list on July 30 by Andrew Haley regarding an ill-advised hard-coded timeout.  Andrew's problem has been fixed upstream now, but if you were running into that exact problem, using --lazy-conversion would have resolved it.  Looking at the code now, I see there is a second hard-coded timeout.  The one I got rid of was where the main operf thread is waiting for the oper_read_pid to finish.  There's another one, where the operf_read_pid is waiting for yet another process to finish . . .  which was started via exec to do the JIT dump conversion.  The timeout for the actual JIT dump conversion is 2 seconds. It appears you've hit that limit.

I'm attaching a patch that should resolve this, if you could please test it.

Thanks.
-Maynard
> 
> Brian
> 
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