linux-kernel - Re: [PATCH 2/3] perf: Account freq events globally

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Message-ID: <20130809103323.GE1045@krava.brq.redhat.com>
Date:	Fri, 9 Aug 2013 12:33:23 +0200
From:	Jiri Olsa <jolsa@...hat.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 2/3] perf: Account freq events globally

On Fri, Aug 02, 2013 at 06:29:55PM +0200, Frederic Weisbecker wrote:
> Freq events may not always be affine to a particular CPU. As such,
> account_event_cpu() may crash if we account per cpu a freq event
> that has event->cpu == -1.
> 
> To solve this, lets account freq events globally. In practice
> this doesn't change much the picture because perf tools create
> per-task perf events with one event per CPU by default. Profiling a
> single CPU is usually a corner case so there is no much point in
> optimizing things that way.
> 
> Reported-by: Jiri Olsa <jolsa@...hat.com>
> Suggested-by: Peter Zijlstra <peterz@...radead.or>
> Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Ingo Molnar <mingo@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Jiri Olsa <jolsa@...hat.com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
> Cc: Stephane Eranian <eranian@...gle.com>

no more OOPSes ;-)

Tested-by: Jiri Olsa <jolsa@...hat.com
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