Re: [PATCH 1/5] perf, x86: Don't assume the alternative cycles encoding is architectural

Peter Zijlstra
2012-06-06T14:53:15Z

On Wed, 2012-06-06 at 07:49 -0700, Andi Kleen wrote:

> Is this for the intel_pmu or for the core_pmu?
>
> > + .pebs_aliases = intel_pebs_aliases_core2,

intel_pmu, we don't actually support PEBS on first gen. core I think.

> In any case since the code later does
>
> version = eax.split.version_id;
> if (version < 2)
> x86_pmu = core_pmu;
> else
> x86_pmu = intel_pmu;
>
> so core_pmu would be active even without model check, which would
> be still wrong.

By not setting pebs_aliases for core_pmu,

> So your patch would fix the problem iff you only fill in the pebs_aliases
> in the model number switch for known Core model numbers.

+ if (event->attr.precise_ip && x86_pmu.pebs_aliases)
+ x86_pmu.pebs_aliases(event);

Never happens, and we're happy again.