Date: Wed, 28 Sep 2005 01:24:45 +0200 (CEST) From: "Niklas Sorensson" <nik@cs.chalmers.se> To: freebsd-current@freebsd.org Subject: hwpmc & sampling Message-ID: <52420.83.226.117.75.1127863485.squirrel@webmail.chalmers.se>
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Hello,
I just started looking into the hwpmc support, but I am having trouble
running pmcstat in sampling mode. Here's an example of the symptoms:
nik> time pmcstat -P instructions -O samples.out ./minisat_static
~/work/benchmarks/sat/standard_mix/f2clk_30.shuffled.cnf > /dev/null
real 0m24.728s
user 0m0.001s
sys 0m0.004s
nik> pmcstat -R samples.out | grep sample | wc -l
289
I would expect quite a lot more samples for a program that runs for
more than 20 seconds. Am I doing something wrong, or does this mean
that there is something wrong with sampling? Just counting seems to
work as expected, although I have not tested very much so far.
I am running on a current (i386) from a couple of days ago on an
amd64 machine.
Btw, I needed to add apic to my kernel config for hwpmc to. I guess
this should be documented somewhere?
/Niklas
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