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From: Robert Watson <rwatson@FreeBSD.org>
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To: Andrew Gallatin <gallatin@cs.duke.edu>
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Cc: current@FreeBSD.org
Subject: Re: The sixty second pmc howto
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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