linux-kernel - Re: [PATCH] perf_events: improve x86 event scheduling

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Message-ID: <bd4cb8901001171353v6984e89blf78b1a11788552a@mail.gmail.com>
Date:	Sun, 17 Jan 2010 22:53:43 +0100
From:	Stephane Eranian <eranian@...gle.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, mingo@...e.hu, paulus@...ba.org,
	davem@...emloft.net, perfmon2-devel@...ts.sf.net
Subject: Re: [PATCH] perf_events: improve x86 event scheduling

hi,

Will repost a new version of the patch with these changes.

On Sun, Jan 17, 2010 at 5:19 PM, Frederic Weisbecker <fweisbec@...il.com> wrote:
> On Sun, Jan 17, 2010 at 03:42:16PM +0100, Stephane Eranian wrote:
>> Frederic,
>>
>>
>> Here is what I have now in the x86 code.
>>
>> As for your comment on disabling the x86 event, we don't
>> need to do this because it is not actually activated yet when
>> we return from hw_perf_group_sched_in(). Activation occurs
>> really in hw_perf_enable().
>
>
> Ah, indeed.
>
>
>>
>>
>> static int x86_event_sched_in(struct perf_event *event,
>>                           struct perf_cpu_context *cpuctx, int cpu)
>> {
>>         int ret = 0;
>>
>>         event->state = PERF_EVENT_STATE_ACTIVE;
>>         event->oncpu = cpu;
>>         event->tstamp_running += event->ctx->time - event->tstamp_stopped;
>>
>>         if (is_software_event(event))
>>                 ret = event->pmu->enable(event);
>>
>>         if (!ret && !is_software_event(event))
>>                 cpuctx->active_oncpu++;
>>
>>         if (!ret && event->attr.exclusive)
>>                 cpuctx->exclusive = 1;
>>
>>         return ret;
>> }
>>
>> static void x86_event_sched_out(struct perf_event *event,
>>                             struct perf_cpu_context *cpuctx, int cpu)
>> {
>>         event->state = PERF_EVENT_STATE_INACTIVE;
>>         event->oncpu = -1;
>>
>>         event->tstamp_running -= event->ctx->time - event->tstamp_stopped;
>>
>>         if (is_software_event(event))
>>                 event->pmu->disable(event);
>>
>>         if (!is_software_event(event))
>>                 cpuctx->active_oncpu--;
>>
>>         if (event->attr.exclusive || !cpuctx->active_oncpu)
>>                 cpuctx->exclusive = 0;
>> }
>
>
>
> Yeah looks good.
>
> Thanks.
>
>



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Stephane Eranian  | EMEA Software Engineering
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