From: Andi Kleen <andi@firstfloor.org>
To: AmirReza Ghods <ar.ghods@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: Does perf record support event multiplexing?
Date: Wed, 22 Jan 2014 20:51:53 -0800 [thread overview]
Message-ID: <874n4v1es6.fsf@tassilo.jf.intel.com> (raw)
In-Reply-To: <CAOJauOAJbbjP6kR_op4bzncDajjOZvN0YWf9+scYjpHrJeLTOg@mail.gmail.com> (AmirReza Ghods's message of "Tue, 21 Jan 2014 13:34:15 -0500")
AmirReza Ghods <ar.ghods@gmail.com> writes:
> I noticed that "perf record" does not calculate the true value for the
> number of event's counts in the case of having more events than
> hardware counters.
> But in pef stat it does and there is a time interpolation algorithm
> for estimating and correcting the true value.
> Also I saw a patch for Perf's source code that implimented time
> interpolation for Perf in record mode but it did not include in the
> next official realses of Perf. I just want to know that is there any
> technical difficulty for implimenting this feature in "perf record" or
> not?
Why would you care about the exact sample count for perf report?
The only thing that counts in such a histogram is the percent
relationships, which would stay the same if the numbers
were scaled up.
-Andi
--
ak@linux.intel.com -- Speaking for myself only
next prev parent reply other threads:[~2014-01-23 4:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-21 18:34 Does perf record support event multiplexing? AmirReza Ghods
2014-01-23 4:51 ` Andi Kleen [this message]
2014-01-27 21:14 ` AmirReza Ghods
2014-01-29 6:49 ` Namhyung Kim
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