Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755849AbaAVTzN (ORCPT ); Wed, 22 Jan 2014 14:55:13 -0500 Received: from mail-qc0-f178.google.com ([209.85.216.178]:41228 "EHLO mail-qc0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752786AbaAVTzK (ORCPT ); Wed, 22 Jan 2014 14:55:10 -0500 MIME-Version: 1.0 In-Reply-To: References: <1390376734-6800-1-git-send-email-vincent.guittot@linaro.org> From: Paul Turner Date: Wed, 22 Jan 2014 11:54:39 -0800 Message-ID: Subject: Re: [PATCH] Revert "sched: Fix sleep time double accounting in enqueue entity" To: Benjamin Segall Cc: Vincent Guittot , Peter Zijlstra , LKML , Ingo Molnar , Alex Shi , Linaro Kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 22, 2014 at 9:53 AM, wrote: > Vincent Guittot writes: > >> 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 > Unless paul wants to squash this into a possible change to the if > (wakeup) stuff: > Reviewed-by: Ben Segall > I can send that separately as Vincent suggests. This is good to go. >> >> --- >> 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 */ -- 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/