From: Vince Weaver <vincent.weaver@maine.edu>
To: Keno Fischer <kfischer@college.harvard.edu>
Cc: Andi Kleen <andi@firstfloor.org>, linux-perf-users@vger.kernel.org
Subject: Re: Sampling hardware counter values with timers
Date: Fri, 13 May 2016 13:42:52 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.2.20.1605131341350.19648@macbook-air> (raw)
In-Reply-To: <CAEoGj_-0GEadeBKQjBmMXiQmAp1839WqkLqDcnJmkB_LEOO3Qg@mail.gmail.com>
On Fri, 13 May 2016, Keno Fischer wrote:
> Thanks. I know that perf sample works this way, but I didn't think it
> was possible to have it sample a specified counter. Is it? `perf stat
> -I` looks exactly like what I need, but it looks like the maximum
> frequency is 10Hz. I was hoping for a higher frequency (& ideally
> something that
> doesn't require switching back into user space and calling `read`).
you can easily hack perf -I to sample faster than 10Hz, but if you sample
much more often than that you're going to start ending up with a lot of
perf_event measurement overhead in your data.
Vince
next prev parent reply other threads:[~2016-05-13 17:43 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
2016-05-13 14:44 ` Keno Fischer
2016-05-13 17:42 ` Vince Weaver [this message]
2016-05-13 18:26 ` Keno Fischer
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