linux-kernel - Re: [PATCH 1/1] Fix number of events displayed in header

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Message-ID: <1332274191.18960.459.camel@twins>
Date:	Tue, 20 Mar 2012 21:09:51 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Ashay Rane <ashay.r@...il.com>
Cc:	David Ahern <dsahern@...il.com>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	linux-perf-users@...r.kernel.org,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org,
	Ashay Rane <ashay.rane@...c.utexas.edu>
Subject: Re: [PATCH 1/1] Fix number of events displayed in header

On Tue, 2012-03-20 at 15:04 -0500, Ashay Rane wrote:
> Oh, okay. Thanks for the clarification!
> 
> However, my reasoning behind including the actual count of the events
> was that (as far as I can tell) it is not displayed in any of the perf
> report outputs. I understand that the count is not precise (because of
> sampling errors) but the sampling frequency (-F) can always be
> adjusted to get a more accurate number.
> 
> With the inclusion of the count, it then becomes possible to compare
> multiple different versions of a program. Hence the patch.

I'm okay if you change the wording of the existing message to be
clearer. I'm also okay if you add this extra information if you find
this useful.

In that case, also have a look at the data generated by perf record -s,
this dumps a PERF_RECORD_READ of the actual counter value at the exit of
every task [doesn't work with per-cpu counters].


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