Re: [PATCH 02/10] perf/x86: Improve HT workaround GP counter constraint

From: Peter Zijlstra
Date: Fri May 22 2015 - 09:25:22 EST


On Fri, May 22, 2015 at 06:05:49AM -0700, Stephane Eranian wrote:
> > I bet you tested the exclusive events earlier :-) Its one of the bugs,
> > the n_excl accounting is leaking up. Once !0 it stays !0.
>
> So you're saying intel_put_excl_constraint() does not do the --n_excl?

No it does, but we call get_events_constraints() every time we do
x86_schedule_events(), and put_events_constraints() only on
x86_pmu_del(). This means we call get() much more than we put().

Therefore leak up.
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