hwpmc & sampling
Andrew Gallatin
gallatin at cs.duke.edu
Fri May 6 08:24:44 PDT 2005
Hi,
I was very excited to see the recent import of the hwpmc code. I'd
like to do essentially what DCPI and Iprobe did on alpha and have a
way of doing system-wide sampling based profiling. Eg, sample
the PC every so many clock ticks, or every so many instructions,
or cache misses, etc.
My current test box is a HTT P4 box, and I admit that I know nothing
about P4s. Can you tell me the correct incantation to use to get
hwpmc in FreeBSD to do this for me? What I've tried isn't working,
but I may just be an idiot.
My first guess was this:
# pmcstat -O /tmp/sample.stat -n 32768 -S tsc
pmcstat: ERROR: Cannot allocate system-mode pmc with specification "tsc": Function not implemented
I didn't have any more luck with what I assume is sampling based on
instructions:
# pmcstat -O /tmp/sample.stat -n 32768 -S p4-instr-retired
pmcstat: ERROR: Cannot allocate system-mode pmc with specification "p4-instr-retired": Function not implemented
Thanks,
Drew
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