Re: [PATCH -tip] perf, x86: Make a second write to performancecounter if needed

From: Lin Ming
Date: Tue Jun 08 2010 - 05:20:26 EST

On Mon, 2010-06-07 at 17:48 +0800, Peter Zijlstra wrote:
> 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.

I tested this patch and it works well for pre-defined events.

Lin Ming

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