Re: [RFC][PATCH v2 06/11] perf: core, export pmus via sysfs

From: Ingo Molnar
Date: Wed May 19 2010 - 03:24:13 EST



* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, 2010-05-19 at 09:06 +0200, Borislav Petkov wrote:
> >
> > have we considered the per-cpu granularity of MCEs
> > here and if yes, how to represent that?
>
> Uhm, by opening the MCE event on a particular cpu?
> Remember that sys_perf_event_open() has a cpu target.
>
> The thing is, CPUs are assumed symmetric, thus also all
> MCE events are symmetric, one CPU cannot generate other
> MCE than another. So the only thing that differs is
> where you want to listen for them.

Note, this does not preclude Linux from supporting
assymetric MP, should the need arise: if MP assymetry is
supported then that can (and should) be expressed in the
sysfs topology accordingly - and the moment the assymetric
MP topology is enumerated in sysfs it gives a place for
the different event_source's to live there as well.

Thanks,

Ingo
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