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Subject: Re: [PATCH -tip] perf, x86: Make a second write to performance
 counter if needed
From: Peter Zijlstra <peterz@infradead.org>
To: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Ingo Molnar <mingo@elte.hu>, Robert Richter <robert.richter@amd.com>,
       LKML <linux-kernel@vger.kernel.org>, Lin Ming <ming.m.lin@intel.com>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
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Date: Mon, 07 Jun 2010 11:48:05 +0200
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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.