Profiling code execution on amd64?

Steve Kargl sgk at
Fri Jan 14 04:05:49 UTC 2011

On Thu, Jan 13, 2011 at 10:08:30PM -0500, Ryan Stone wrote:
> I would suggest using hwpmc for profiling:
> # kldload hwpmc
> # pmcstat -S unhalted-cycles -O /tmp/samples.out ../penetration
> # pmcstat -R /tmp/samples.out -G /tmp/penetration.txt
> You can also get pmcstat to generate gprof-compatible output with -g,
> but I never use the mode so I'm really not sure what it gives you.  I
> think that you have to run gprof on the output or something, but don't
> hold me to that.

Thanks.  I'll give it a try, but my initial attempt seems to
indicate that one needs to be root to use hwpmc.  

laptop:kargl[210] pmcstat -S unhalted-cycles -O /tmp/samples.out ../penetration
pmcstat: ERROR: Cannot allocate system-mode pmc with specification
"unhalted-cycles": Operation not permitted


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