From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750897AbbHOEYs (ORCPT ); Sat, 15 Aug 2015 00:24:48 -0400 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:57319 "EHLO lgemrelse6q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750739AbbHOEYr (ORCPT ); Sat, 15 Aug 2015 00:24:47 -0400 X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Sat, 15 Aug 2015 13:24:12 +0900 From: Byungchul Park To: "T. Zhou" Cc: mingo@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, yuyang.du@intel.com Subject: Re: [PATCH] sched: sync with the cfs_rq when changing sched class Message-ID: <20150815042412.GS3956@byungchulpark-X58A-UD3R> References: <1439445355-24137-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 On Fri, Aug 14, 2015 at 08:59:02PM +0800, T. Zhou wrote: > Hi, > > On Thu, Aug 13, 2015 at 02:55:55PM +0900, byungchul.park@lge.com wrote: > > +static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) > > +{ > > + se->avg.last_update_time = cfs_rq->avg.last_update_time; > > + cfs_rq->avg.load_avg += se->avg.load_avg; > > + cfs_rq->avg.load_sum += se->avg.load_sum; > > + cfs_rq->avg.util_avg += se->avg.util_avg; > > + cfs_rq->avg.util_sum += se->avg.util_sum; > > +} > > I see this function is used in enqueue_entity_load_avg() also. > In tip tree code, enqueue_entity_load_avg() uses cfs_rq_clock_task() > as se->last_update_time in migration condition. > Here, you use cfs_rq->avg.last_update_time as se->last_update_time. > If se->last_update_time is different, next decay may be different too. > Just from inspecting code, maybe some reasonable there? hello zhou, update_cfs_rq_load_avg() would update cfs_rq->avg.last_update_time to now, which is returned from cfs_rq_clock_task(). :) thanks, byungchul > > Thanks > > +static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) > > +{ > > + __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), > > + &se->avg, se->on_rq * scale_load_down(se->load.weight), > > + cfs_rq->curr == se, NULL); > > + > > + cfs_rq->avg.load_avg = > > + max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0); > > + cfs_rq->avg.load_sum = > > + max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0); > > + cfs_rq->avg.util_avg = > > + max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0); > > + cfs_rq->avg.util_sum = > > + max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0); > > +} > > + > > /* Add the load generated by se into cfs_rq's load average */ > > static inline void > > enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) > > @@ -2717,27 +2742,20 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) > > u64 now = cfs_rq_clock_task(cfs_rq); > > int migrated = 0, decayed; > > > > - if (sa->last_update_time == 0) { > > - sa->last_update_time = now; > > + if (sa->last_update_time == 0) > > migrated = 1; > > - } > > - else { > > + else > > __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa, > > - se->on_rq * scale_load_down(se->load.weight), > > - cfs_rq->curr == se, NULL); > > - } > > + se->on_rq * scale_load_down(se->load.weight), > > + cfs_rq->curr == se, NULL); > > > > decayed = update_cfs_rq_load_avg(now, cfs_rq); > > > > cfs_rq->runnable_load_avg += sa->load_avg; > > cfs_rq->runnable_load_sum += sa->load_sum; > > > > - if (migrated) { > > - cfs_rq->avg.load_avg += sa->load_avg; > > - cfs_rq->avg.load_sum += sa->load_sum; > > - cfs_rq->avg.util_avg += sa->util_avg; > > - cfs_rq->avg.util_sum += sa->util_sum; > > - } > > + if (migrated) > > + attach_entity_load_avg(cfs_rq, se); > > > > if (decayed || migrated) > > update_tg_load_avg(cfs_rq, 0); > > @@ -7911,17 +7929,7 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p) > > > > #ifdef CONFIG_SMP > > /* Catch up with the cfs_rq and remove our load when we leave */ > > - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq), &se->avg, > > - se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL); > > - > > - cfs_rq->avg.load_avg = > > - max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0); > > - cfs_rq->avg.load_sum = > > - max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0); > > - cfs_rq->avg.util_avg = > > - max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0); > > - cfs_rq->avg.util_sum = > > - max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0); > > + detach_entity_load_avg(cfs_rq, se); > > #endif > > } > > > > @@ -7938,6 +7946,11 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p) > > */ > > se->depth = se->parent ? se->parent->depth + 1 : 0; > > #endif > > + > > +#ifdef CONFIG_SMP > > + /* synchronize task with its cfs_rq */ > > + attach_entity_load_avg(cfs_rq_of(&p->se), &p->se); > > +#endif > > if (!task_on_rq_queued(p)) > > return; > > > > @@ -8023,16 +8036,7 @@ static void task_move_group_fair(struct task_struct *p, int queued) > > > > #ifdef CONFIG_SMP > > /* synchronize task with its prev cfs_rq */ > > - if (!queued) > > - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)), > > - &se->avg, se->on_rq * scale_load_down(se->load.weight), > > - cfs_rq->curr == se, NULL); > > - > > - /* remove our load when we leave */ > > - cfs_rq->avg.load_avg = max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0); > > - cfs_rq->avg.load_sum = max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0); > > - cfs_rq->avg.util_avg = max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0); > > - cfs_rq->avg.util_sum = max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0); > > + detach_entity_load_avg(cfs_rq, se); > > #endif > > set_task_rq(p, task_cpu(p)); > > se->depth = se->parent ? se->parent->depth + 1 : 0; > > @@ -8042,11 +8046,7 @@ static void task_move_group_fair(struct task_struct *p, int queued) > > > > #ifdef CONFIG_SMP > > /* Virtually synchronize task with its new cfs_rq */ > > - p->se.avg.last_update_time = cfs_rq->avg.last_update_time; > > - cfs_rq->avg.load_avg += p->se.avg.load_avg; > > - cfs_rq->avg.load_sum += p->se.avg.load_sum; > > - cfs_rq->avg.util_avg += p->se.avg.util_avg; > > - cfs_rq->avg.util_sum += p->se.avg.util_sum; > > + attach_entity_load_avg(cfs_rq, se); > > #endif > > } > > -- > Tao > -- > -- > 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/