Re: [BUG] perf: sharing of cpuctx between core and ibs PMU causesproblems

From: Peter Zijlstra
Date: Thu Aug 09 2012 - 14:08:31 EST


On Thu, 2012-08-09 at 16:05 +0200, Stephane Eranian wrote:
> > uncore PMU does not have this issue because uncore_pmu->task_ctx_nr
> > is 'perf_invalid_context'. find_pmu_context() always return NULL in
> > that case.
> >
> Yes, I think IBS should do the same and that should fix the problem
> there too. Will try that.

I'm afraid not, per-task profiling with uncore doesn't really make that
much sense. For IBS it does.

We can't share a context with different PMUs, that'll totally mess up
the event scheduling.

We'll have to grow perf_event_task_context with an extra context and
have IBS use that.
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