From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899AbbHNNMX (ORCPT ); Fri, 14 Aug 2015 09:12:23 -0400 Received: from blu004-omc1s5.hotmail.com ([65.55.116.16]:62220 "EHLO BLU004-OMC1S5.hotmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752753AbbHNNMV (ORCPT ); Fri, 14 Aug 2015 09:12:21 -0400 X-Greylist: delayed 479 seconds by postgrey-1.27 at vger.kernel.org; Fri, 14 Aug 2015 09:12:21 EDT X-TMN: [oUhtIrD4HlRGFNN7OighrlP6aHYjGHWY] X-Originating-Email: [t.s.zhou@hotmail.com] Message-ID: Date: Fri, 14 Aug 2015 20:59:02 +0800 From: "T. Zhou" To: byungchul.park@lge.com 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 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: <1439445355-24137-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-OriginalArrivalTime: 14 Aug 2015 13:04:20.0912 (UTC) FILETIME=[BC288B00:01D0D691] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? 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 --