PMC (performance counters) problems - kernel panic in 6-beta1

Joseph Koshy jkoshy at FreeBSD.ORG
Fri Jul 29 03:11:07 GMT 2005


 
> Another question, what is the difference of -s versus -S and -p versus
> -P, respectively?

-S and -P turn on sampling.  -S does 'whole system' sampling.  -P is
process specific (i.e., the counters only count when the target process(es)
are running).

So:

 # pmcstat -S instructions -O /tmp/foo.out

will collect samples.

 # pmcstat -g -R /tmp/foo.out

will convert the sample log to gprof(1) compatible 'gmon.out' files.

Sampling on the AMD64 requires a patch to current [I'll commit it
shortly].

> Thanks for great work.

Thanks.

Regards,
Koshy
<jkoshy at freebsd.org>



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