The sixty second pmc howto
Robert Watson
rwatson at FreeBSD.org
Thu Feb 23 07:32:08 PST 2006
On Thu, 23 Feb 2006, Andrew Gallatin wrote:
> Robert Watson writes:
>
> > (2) Run "pmcstat -S instructions -O /tmp/sample.out" to start sampling of
> > instruction retirement events, saving the results to /tmp/sample.out.
>
> Dumb question, but what does "instructions" really mean? The number of
> instructions, the time spent executing them, ?
pmcstat magically translates 'instructions' into 'p4-instr-retired', which
might well refer to what happens to an instruction when it is believed to have
successfully executed. Presumably this happens once you know it hasn't been
mispredicted, etc, but I'm sure someone can give a better and more detailed
answer.
Robert N M Watson
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