linux-kernel - Re: [PATCH 00/12] perf lock: New subcommand "perf lock", for analyzing lock statistics

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Message-ID: <20100201092239.GA22578@elte.hu>
Date:	Mon, 1 Feb 2010 10:22:39 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Jens Axboe <jens.axboe@...cle.com>,
	Hitoshi Mitake <mitake@....info.waseda.ac.jp>,
	linux-kernel@...r.kernel.org, Paul Mackerras <paulus@...ba.org>,
	Tom Zanussi <tzanussi@...il.com>,
	Steven Rostedt <srostedt@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: Re: [PATCH 00/12] perf lock: New subcommand "perf lock", for
 analyzing  lock statistics


* Peter Zijlstra <peterz@...radead.org> wrote:

> On Sun, 2010-01-31 at 22:07 +0100, Frederic Weisbecker wrote:
> > 
> > - We are using the -M option from perf tools which multiplexes every
> >   event buffers, which means every cpu commit their lock events in
> >   the same buffer. Couple that with the two above reasons, it's supposed
> >   to scale at worst.
> 
> Why are you doing that? That seems like asking for trouble.. 

But as i said i already tried with -M off and it didnt cure the slowdown.

that -M was just copied over from perf sched (where it makes sense).

	Ingo
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