From: Andi Kleen <andi@firstfloor.org>
To: Keno Fischer <kfischer@college.harvard.edu>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: Sampling hardware counter values with timers
Date: Fri, 13 May 2016 06:40:41 -0700 [thread overview]
Message-ID: <87vb2ikrdy.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <CAEoGj_-43BRwknevsRtZWpwLuF5sh=mYs5J36swowB17FwkWxg@mail.gmail.com> (Keno Fischer's message of "Fri, 13 May 2016 00:00:16 -0400")
Keno Fischer <kfischer@college.harvard.edu> writes:
> Hello everyone,
>
> I was wondering if it is possible (either using the `perf` user space
> tool or using the perf_events API) to periodically sample the value of
> a hardware counter (in my particular case I'd like to sample the
> retired-branch-counter). I know it is possible to do the opposite
> (i.e. sample a timestamp every specified number of branches), but I
> wasn't able to see an easy way to sample the hardware counter at a
> specified frequency. Is this possible?
perf record works this way by default. The counter period is dynamically
adjusted for a given frequency. The default frequency is 1000.
You can set it with -F.
Another alternative is to use perf stat -I ... if you only need the counts.
-Andi
next prev parent reply other threads:[~2016-05-13 13:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-13 4:00 Sampling hardware counter values with timers Keno Fischer
2016-05-13 13:40 ` Andi Kleen [this message]
2016-05-13 14:44 ` Keno Fischer
2016-05-13 17:42 ` Vince Weaver
2016-05-13 18:26 ` Keno Fischer
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