Re: [RFC PATCH] perf: honoring cpuid for number of fixed counters

From: Peter Zijlstra
Date: Thu Jun 04 2015 - 07:49:36 EST


On Thu, Jun 04, 2015 at 12:35:08PM +0200, Imre Palik wrote:
> On 06/03/15 10:36, Peter Zijlstra wrote:
> > Further, the Intel Arch PerfMon v2 spec actually specifies there to be 3
> > fixed function counters.
> >
> > So anything that says it is v2+ and does not have the 3, is non
> > compliant.
> >
> > I would suggest you go fix your hypervisor.
>
> If I set up the hypervisor to advertise Arch PerfMon v1 (0 fixed
> counters), then without my patch, perf still tries to use fixed
> counters. So something is clearly broken here.

So the code you deleted does if (version > 1), and last I checked that
should return false if version == 1.

So please check what's happening there first.
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