linux-kernel - Re: [PATCH -tip] perf, x86: Make a second write to performance counter if needed

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Message-ID: <1275904085.1645.555.camel@laptop>
Date:	Mon, 07 Jun 2010 11:48:05 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Cyrill Gorcunov <gorcunov@...nvz.org>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Robert Richter <robert.richter@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Lin Ming <ming.m.lin@...el.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Frédéric Weisbecker <fweisbec@...il.com>
Subject: Re: [PATCH -tip] perf, x86: Make a second write to performance
 counter if needed

On Thu, 2010-06-03 at 01:23 +0400, Cyrill Gorcunov wrote:
> On Netburst PMU we need a second write to a performance counter
> due to cpu erratum.
> 
> A simple flag test instead of alternative instructions was choosen
> because wrmsrl is already a macro and if virtualization is turned
> on will need an additional wrapper call which is more expencise.
> 
> nb: we should propably switch to jump-labels as only this facility
> reach the mainline.

OK. Thanks Cyrill.


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