Date: Wed, 28 Sep 2005 15:22:14 +0530 From: Joseph Koshy <joseph.koshy@gmail.com> To: Niklas Sorensson <nik@cs.chalmers.se> Cc: freebsd-current@freebsd.org Subject: Re: hwpmc & sampling Message-ID: <84dead72050928025251c032f7@mail.gmail.com> In-Reply-To: <52420.83.226.117.75.1127863485.squirrel@webmail.chalmers.se> References: <52420.83.226.117.75.1127863485.squirrel@webmail.chalmers.se>
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Niklas, ns> time pmcstat -P instructions -O samples.out ./minisat_static ns> I would expect quite a lot more samples for a program that ns> runs for more than 20 seconds. Am I doing something wrong, Could you check whether the output of "pmccontrol -s", shows the 'interrupts dropped due to lack of space' count as non-zero? If it is, you will need to increase the tunable "kern.hwpmc.nsamples" till you get clean runs. I guess I should make pmcstat check and warn the user about sampling stalls encountered. nc> Btw, I needed to add apic to my kernel config for hwpmc to. nc> I guess this should be documented somewhere? It seems to be needed on the i386, but not on the amd64. Will fix. -- FreeBSD Volunteer, http://people.freebsd.org/~jkoshy
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