Hey gents,

I probably have a dumb question (if there are dumb questions...).

I always thought that system level profiling tools/framework like perf-events 
or Oprofile or Caliper ... being used to profile java based applications were 
only good to show the high-level breakdown between CPU time exec'ed in java 
code and CPU time exec'ed in 'native' (JNI) code, i.e. something like 
20% spent exec'ing JNI code vs. 80% spent in exec'ing pure java code.

But if you want the breakdown of the 80% spent in java code, i.e. the perf java 
methods breakdown, etc.... You need to use a java profiler (Jrockit Mission 
Control, Jprofiler, etc...) and can't expect this information to be provided by 
perf-events / Oprofile / Caliper /etc...

Comments ?

++Cyrille

-----Original Message-----
From: [email protected] 
[mailto:[email protected]] On Behalf Of Stefan Hajnoczi
Sent: Wednesday, August 31, 2011 9:36 AM
To: Geoffrey Blake
Cc: [email protected]
Subject: Re: Profiling Java code running on Sun HotSpot JVM with linux perf

On Tue, Aug 30, 2011 at 9:03 PM, Geoffrey Blake <[email protected]> 
wrote:
> Hi all,
>
> I am trying to profile some java server applications using %>perf 
> record -a, and as expected the majority of the execution time of these 
> applications is spent within jit'ed java code.  According to these 
> lists, the jit should be outputting a /tmp/perf-$pid.map file for each 
> thread being jit'ed.  The Sun JIT does not seem to have this output 
> enabled by default.  Does anyone here know what options I need to set 
> on the command line to get the JVM to output the symbol map files from 
> the JIT?

I don't know the answer but if you don't get one here you could check the 
OProfile mailing list.  I believe there was a solution for JIT compilers with 
OProfile and people probably got popular JVMs like HotSpot working.  That might 
reveal what support HotSpot has for doing this.

Stefan
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