Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754112AbaAVHue (ORCPT ); Wed, 22 Jan 2014 02:50:34 -0500 Received: from mail-ob0-f177.google.com ([209.85.214.177]:64078 "EHLO mail-ob0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750781AbaAVHud (ORCPT ); Wed, 22 Jan 2014 02:50:33 -0500 MIME-Version: 1.0 In-Reply-To: <1390376734-6800-1-git-send-email-vincent.guittot@linaro.org> References: <1390376734-6800-1-git-send-email-vincent.guittot@linaro.org> From: Vincent Guittot Date: Wed, 22 Jan 2014 08:50:12 +0100 Message-ID: Subject: Re: [PATCH] Revert "sched: Fix sleep time double accounting in enqueue entity" To: Peter Zijlstra , Paul Turner Cc: Ingo Molnar , linux-kernel , Benjamin Segall , Alex Shi , "linaro-kernel@lists.linaro.org" , Vincent Guittot 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 Paul, I let you send a patch that will add comment and move the "if (wakeup) logic" ? Regards Vincent On 22 January 2014 08:45, Vincent Guittot wrote: > This reverts commit 282cf499f03ec1754b6c8c945c9674b02631fb0f. > > With the current implementation, the load average statistics of a sched entity > change according to other activity on the CPU even if this activity is done > between the running window of the sched entity and have no influence on the > running duration of the task. > > When a task wakes up on the same CPU, we currently update last_runnable_update > with the return of __synchronize_entity_decay without updating the > runnable_avg_sum and runnable_avg_period accordingly. In fact, we have to sync > the load_contrib of the se with the rq's blocked_load_contrib before removing > it from the latter (with __synchronize_entity_decay) but we must keep > last_runnable_update unchanged for updating runnable_avg_sum/period during the > next update_entity_load_avg. > > Signed-off-by: Vincent Guittot > > --- > kernel/sched/fair.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index e64b079..6d61f20 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2365,13 +2365,7 @@ static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq, > } > wakeup = 0; > } else { > - /* > - * Task re-woke on same cpu (or else migrate_task_rq_fair() > - * would have made count negative); we must be careful to avoid > - * double-accounting blocked time after synchronizing decays. > - */ > - se->avg.last_runnable_update += __synchronize_entity_decay(se) > - << 20; > + __synchronize_entity_decay(se); > } > > /* migrated tasks did not contribute to our blocked load */ > -- > 1.7.9.5 > -- 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/