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Subject: Re: [PATCH] perf_events: improve x86 event scheduling (v5)
From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, paulus@samba.org,
       davem@davemloft.net, fweisbec@gmail.com, perfmon2-devel@lists.sf.net,
       eranian@gmail.com
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Date: Thu, 21 Jan 2010 11:46:25 +0100
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On Thu, 2010-01-21 at 11:43 +0100, Stephane Eranian wrote:
> On Thu, Jan 21, 2010 at 11:36 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Mon, 2010-01-18 at 10:58 +0200, Stephane Eranian wrote:
> >>  void hw_perf_enable(void)
> >>  {
> >
> >
> >> +               cpuc->n_added = 0;
> >> +               perf_events_lapic_init();
> >
> > Just wondering, why do we need that lapic_init() there?
> >
> I think I picked it up from x86_pmu_enable(). I don't think
> you necessarily need it here. Not clear to me why it was
> in x86_pmu_enable() to begin with.

Right, wondering about the same ;-)

> I will post a new version of the patch which fixes some bugs and
> also implements true fast path (reuse of previous assignment). It turned
> out, things were a bit more complicated than what I had in v5.

Could you post a diff against your previous version, I just picked up
-v5 and tidied a few things up and send it mingo wards (although it
appears he hasn't picked it up yet).