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From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: "Yan, Zheng" <zheng.z.yan@intel.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Robert Richter <robert.richter@amd.com>,
	mingo@elte.hu
Subject: Re: [BUG] perf: sharing of cpuctx between core and ibs PMU causes problems
Date: Thu, 09 Aug 2012 20:08:27 +0200	[thread overview]
Message-ID: <1344535707.20277.20.camel@twins> (raw)
In-Reply-To: <CABPqkBT-pvmhyOHfMXs7dXsJXpEVmaSST1xFFHzCu4CDBf7baw@mail.gmail.com>

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.

  reply	other threads:[~2012-08-09 18:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-09  0:51 [BUG] perf: sharing of cpuctx between core and ibs PMU causes problems Stephane Eranian
2012-08-09  6:55 ` Yan, Zheng
2012-08-09 14:05   ` Stephane Eranian
2012-08-09 18:08     ` Peter Zijlstra [this message]
2012-08-09 19:21       ` Stephane Eranian
2012-08-13 10:28         ` Peter Zijlstra
2012-08-13 12:53           ` Stephane Eranian
2012-08-13 15:32             ` Peter Zijlstra
2012-08-13 15:36               ` Stephane Eranian

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