Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751934AbbHMIWF (ORCPT ); Thu, 13 Aug 2015 04:22:05 -0400 Received: from lgeamrelo04.lge.com ([156.147.1.127]:53126 "EHLO lgeamrelo04.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750769AbbHMIWB (ORCPT ); Thu, 13 Aug 2015 04:22:01 -0400 X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Thu, 13 Aug 2015 17:21:27 +0900 From: Byungchul Park To: Peter Zijlstra Cc: mingo@kernel.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: <20150813082127.GO3956@byungchulpark-X58A-UD3R> References: <1439445355-24137-1-git-send-email-byungchul.park@lge.com> <20150813074600.GB16853@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150813074600.GB16853@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: 2777 Lines: 70 On Thu, Aug 13, 2015 at 09:46:00AM +0200, Peter Zijlstra wrote: > On Thu, Aug 13, 2015 at 02:55:55PM +0900, byungchul.park@lge.com wrote: > > @@ -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 > > } > > Can't we go one further and do: > > static void task_move_group_fair(struct task_struct *p) > { > struct rq *rq = task_rq(p); > > switched_from_fair(rq, p); > set_task_rq(p, task_cpu(p); > switched_to_fair(rq, p); > } it looks nice, but i will think more.. > > switched_from already does the vruntime and load_avg thing, > switched_to should do the reverse, although it currently doesn't appear > to put the load_avg back. yuyang said that switched_to don't need to consider task's load because it can have meaningless value. but i think considering task's load is better than leaving it unattended at all. and we can also use switched_to if we consider task's load in switched_to. thanks, byungchul > > -- > 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/ -- 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/