From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934585Ab3BTJa7 (ORCPT ); Wed, 20 Feb 2013 04:30:59 -0500 Received: from merlin.infradead.org ([205.233.59.134]:53212 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934307Ab3BTJa5 (ORCPT ); Wed, 20 Feb 2013 04:30:57 -0500 Message-ID: <1361352643.10155.4.camel@laptop> Subject: Re: [patch v5 06/15] sched: log the cpu utilization at rq From: Peter Zijlstra To: Alex Shi Cc: torvalds@linux-foundation.org, mingo@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, morten.rasmussen@arm.com Date: Wed, 20 Feb 2013 10:30:43 +0100 In-Reply-To: <1361164062-20111-7-git-send-email-alex.shi@intel.com> References: <1361164062-20111-1-git-send-email-alex.shi@intel.com> <1361164062-20111-7-git-send-email-alex.shi@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2013-02-18 at 13:07 +0800, Alex Shi wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index fcdb21f..b9a34ab 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1495,8 +1495,12 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update) > > static inline void update_rq_runnable_avg(struct rq *rq, int runnable) > { > + u32 period; > __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable); > __update_tg_runnable_avg(&rq->avg, &rq->cfs); > + > + period = rq->avg.runnable_avg_period ? rq->avg.runnable_avg_period : 1; > + rq->util = rq->avg.runnable_avg_sum * 100 / period; > } > > /* Add the load generated by se into cfs_rq's child load-average */ > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 7a19792..ac1e107 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -350,6 +350,9 @@ extern struct root_domain def_root_domain; > > #endif /* CONFIG_SMP */ > > +/* the percentage full cpu utilization */ > +#define FULL_UTIL 100 There's generally a better value than 100 when using computers.. seeing how 100 is 64+32+4. > + > /* > * This is the main, per-CPU runqueue data structure. > * > @@ -481,6 +484,7 @@ struct rq { > #endif > > struct sched_avg avg; > + unsigned int util; > }; > > static inline int cpu_of(struct rq *rq) You don't actually compute the rq utilization, you only compute the utilization as per the fair class, so if there's significant RT activity it'll think the cpu is under-utilized, whihc I think will result in the wrong thing.