Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756886Ab3EFVUO (ORCPT ); Mon, 6 May 2013 17:20:14 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:33374 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756040Ab3EFVUL (ORCPT ); Mon, 6 May 2013 17:20:11 -0400 MIME-Version: 1.0 In-Reply-To: <1365040862-8390-6-git-send-email-alex.shi@intel.com> References: <1365040862-8390-1-git-send-email-alex.shi@intel.com> <1365040862-8390-6-git-send-email-alex.shi@intel.com> From: Paul Turner Date: Mon, 6 May 2013 14:19:37 -0700 Message-ID: Subject: Re: [patch v7 05/21] sched: log the cpu utilization at rq To: Alex Shi Cc: Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Arjan van de Ven , Borislav Petkov , Namhyung Kim , Mike Galbraith , Morten Rasmussen , Vincent Guittot , gregkh@linuxfoundation.org, Preeti U Murthy , Viresh Kumar , LKML , len.brown@intel.com, rafael.j.wysocki@intel.com, jkosina@suse.cz, clark.williams@gmail.com, tony.luck@intel.com, keescook@chromium.org, Mel Gorman , Rik van Riel Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3870 Lines: 113 On Wed, Apr 3, 2013 at 7:00 PM, Alex Shi wrote: > The cpu's utilization is to measure how busy is the cpu. > util = cpu_rq(cpu)->avg.runnable_avg_sum * SCHED_POEWR_SCALE > / cpu_rq(cpu)->avg.runnable_avg_period; > > Since the util is no more than 1, we scale its value with 1024, same as > SCHED_POWER_SCALE and set the FULL_UTIL as 1024. > > In later power aware scheduling, we are sensitive for how busy of the > cpu. Since as to power consuming, it is tight related with cpu busy > time. > > BTW, rq->util can be used for any purposes if needed, not only power > scheduling. > > Signed-off-by: Alex Shi Hmm, rather than adding another variable to struct rq and another callsite where we open code runnable-scaling we should consider at least adding a wrapper, e.g. /* when to_scale is a load weight callers must pass "scale_load(value)" */ static inline u32 scale_by_runnable_avg(struct sched_avg *avg, u32 to_scale) { u32 result = se->avg.runnable_avg_sum * to_scale; result /= (se->avg.runnable_avg_period + 1); return result; } util can then just be scale_by_runnable_avg(&rq->avg, FULL_UTIL) and if we don't need it frequently, it's now simple enough that we don't need to cache it. > --- > include/linux/sched.h | 2 +- > kernel/sched/debug.c | 1 + > kernel/sched/fair.c | 5 +++++ > kernel/sched/sched.h | 4 ++++ > 4 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 5a4cf37..226a515 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -793,7 +793,7 @@ enum cpu_idle_type { > #define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT) > > /* > - * Increase resolution of cpu_power calculations > + * Increase resolution of cpu_power and rq->util calculations > */ > #define SCHED_POWER_SHIFT 10 > #define SCHED_POWER_SCALE (1L << SCHED_POWER_SHIFT) > diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c > index 75024a6..f5db759 100644 > --- a/kernel/sched/debug.c > +++ b/kernel/sched/debug.c > @@ -311,6 +311,7 @@ do { \ > > P(ttwu_count); > P(ttwu_local); > + P(util); > > #undef P > #undef P64 > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 2e49c3f..7124244 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1495,8 +1495,13 @@ 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 = (u64)(rq->avg.runnable_avg_sum << SCHED_POWER_SHIFT) > + / 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 804ee41..8682110 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -351,6 +351,9 @@ extern struct root_domain def_root_domain; > > #endif /* CONFIG_SMP */ > > +/* full cpu utilization */ > +#define FULL_UTIL SCHED_POWER_SCALE > + > /* > * This is the main, per-CPU runqueue data structure. > * > @@ -482,6 +485,7 @@ struct rq { > #endif > > struct sched_avg avg; > + unsigned int util; > }; > > static inline int cpu_of(struct rq *rq) > -- > 1.7.12 > a -- 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/