linux-kernel - Re: [RFC] perf/perf_events: misleading number of samples due to mmap()

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Message-ID: <1276700052.1745.600.camel@laptop>
Date:	Wed, 16 Jun 2010 16:54:12 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	Arnaldo Carvalho de Melo <acme@...radead.org>,
	linux-kernel@...r.kernel.org, mingo@...e.hu, paulus@...ba.org,
	davem@...emloft.net, fweisbec@...il.com,
	perfmon2-devel@...ts.sf.net, eranian@...il.com
Subject: Re: [RFC] perf/perf_events: misleading number of samples due to
 mmap()

On Wed, 2010-06-16 at 16:40 +0200, Stephane Eranian wrote:
> The reason is that perf reports an estimate based on the
> number of bytes written to the buffer divided by the minimal
> sample size of 24 bytes. 

Right, we should change that based on the PERF_SAMPLE flags used. It
will remain an estimate due to the out of band events, but it should be
closer than assuming the minimal sample size.
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