Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756007Ab3HANzd (ORCPT ); Thu, 1 Aug 2013 09:55:33 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:65148 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754803Ab3HANza (ORCPT ); Thu, 1 Aug 2013 09:55:30 -0400 Date: Thu, 1 Aug 2013 15:55:27 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: Jiri Olsa , LKML , Namhyung Kim , Ingo Molnar , Arnaldo Carvalho de Melo , Stephane Eranian Subject: Re: [PATCH 6/8] perf: Account freq events per cpu Message-ID: <20130801135525.GE431@somewhere> References: <1374539466-4799-1-git-send-email-fweisbec@gmail.com> <1374539466-4799-7-git-send-email-fweisbec@gmail.com> <20130801124658.GC1032@krava.brq.redhat.com> <20130801133155.GB27162@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130801133155.GB27162@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3406 Lines: 85 On Thu, Aug 01, 2013 at 03:31:55PM +0200, Peter Zijlstra wrote: > On Thu, Aug 01, 2013 at 02:46:58PM +0200, Jiri Olsa wrote: > > On Tue, Jul 23, 2013 at 02:31:04AM +0200, Frederic Weisbecker wrote: > > > This is going to be used by the full dynticks subsystem > > > as a finer-grained information to know when to keep and > > > when to stop the tick. > > > > > > Original-patch-by: Peter Zijlstra > > > Signed-off-by: Frederic Weisbecker > > > Cc: Jiri Olsa > > > Cc: Peter Zijlstra > > > Cc: Namhyung Kim > > > Cc: Ingo Molnar > > > Cc: Arnaldo Carvalho de Melo > > > Cc: Stephane Eranian > > > --- > > > kernel/events/core.c | 7 +++++++ > > > 1 files changed, 7 insertions(+), 0 deletions(-) > > > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > > index b40c3db..f9bd39b 100644 > > > --- a/kernel/events/core.c > > > +++ b/kernel/events/core.c > > > @@ -141,6 +141,7 @@ enum event_type_t { > > > struct static_key_deferred perf_sched_events __read_mostly; > > > static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); > > > static DEFINE_PER_CPU(atomic_t, perf_branch_stack_events); > > > +static DEFINE_PER_CPU(atomic_t, perf_freq_events); > > > > > > static atomic_t nr_mmap_events __read_mostly; > > > static atomic_t nr_comm_events __read_mostly; > > > @@ -3139,6 +3140,9 @@ static void unaccount_event_cpu(struct perf_event *event, int cpu) > > > } > > > if (is_cgroup_event(event)) > > > atomic_dec(&per_cpu(perf_cgroup_events, cpu)); > > > + > > > + if (event->attr.freq) > > > + atomic_dec(&per_cpu(perf_freq_events, cpu)); > > > } > > > > > > static void unaccount_event(struct perf_event *event) > > > @@ -6473,6 +6477,9 @@ static void account_event_cpu(struct perf_event *event, int cpu) > > > } > > > if (is_cgroup_event(event)) > > > atomic_inc(&per_cpu(perf_cgroup_events, cpu)); > > > + > > > + if (event->attr.freq) > > > + atomic_inc(&per_cpu(perf_freq_events, cpu)); > > > > cpu could be -1 in here.. getting: > > Ho humm, right you are. > > So we have: > > static void account_event_cpu(struct perf_event *event, int cpu) > { > if (event->parent) > return; > > if (has_branch_stack(event)) { > if (!(event->attach_state & PERF_ATTACH_TASK)) > atomic_inc(&per_cpu(perf_branch_stack_events, cpu)); > } > if (is_cgroup_event(event)) > atomic_inc(&per_cpu(perf_cgroup_events, cpu)); > > if (event->attr.freq) > atomic_inc(&per_cpu(perf_freq_events, cpu)); > } > > Where the freq thing is new and shiney, but we already had the other > two. Of those, cgroup events must be per cpu so that should be good, > the branch_stack thing tests ATTACH_TASK, which should also be good, but > leaves me wonder wth they do for those that are attached to tasks. > > But yes, the frequency thing is borken. Aie, so the freq thing, I can either account to all CPUs (inc to all and send an IPI to all), or when the event scheds in/out. Probably we should do the former to avoid sending an IPI at all context switches. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/