From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934237AbeBML2k (ORCPT ); Tue, 13 Feb 2018 06:28:40 -0500 Received: from terminus.zytor.com ([198.137.202.136]:52519 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933926AbeBML2i (ORCPT ); Tue, 13 Feb 2018 06:28:38 -0500 Date: Tue, 13 Feb 2018 03:28:13 -0800 From: tip-bot for Wen Yang Message-ID: Cc: mingo@kernel.org, hpa@zytor.com, peterz@infradead.org, tglx@linutronix.de, jiang.biao2@zte.com.cn, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, wen.yang99@zte.com.cn Reply-To: peterz@infradead.org, tglx@linutronix.de, hpa@zytor.com, mingo@kernel.org, wen.yang99@zte.com.cn, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, jiang.biao2@zte.com.cn In-Reply-To: <1517882148-44599-1-git-send-email-wen.yang99@zte.com.cn> References: <1517882148-44599-1-git-send-email-wen.yang99@zte.com.cn> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched/deadline: Make update_curr_dl() more accurate Git-Commit-ID: 6fe0ce1eb04f99a1eb1eb6e7f775666966cf6c80 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6fe0ce1eb04f99a1eb1eb6e7f775666966cf6c80 Gitweb: https://git.kernel.org/tip/6fe0ce1eb04f99a1eb1eb6e7f775666966cf6c80 Author: Wen Yang AuthorDate: Tue, 6 Feb 2018 09:55:48 +0800 Committer: Ingo Molnar CommitDate: Tue, 13 Feb 2018 11:44:40 +0100 sched/deadline: Make update_curr_dl() more accurate rq->clock_task may be updated between the two calls of rq_clock_task() in update_curr_dl(). Calling rq_clock_task() only once makes it more accurate and efficient, taking update_curr() as reference. Suggested-by: Peter Zijlstra Signed-off-by: Wen Yang Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Jiang Biao Cc: Linus Torvalds Cc: Thomas Gleixner Cc: zhong.weidong@zte.com.cn Link: http://lkml.kernel.org/r/1517882148-44599-1-git-send-email-wen.yang99@zte.com.cn Signed-off-by: Ingo Molnar --- kernel/sched/deadline.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 9bb0e0c..9df0978 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1153,6 +1153,7 @@ static void update_curr_dl(struct rq *rq) struct sched_dl_entity *dl_se = &curr->dl; u64 delta_exec, scaled_delta_exec; int cpu = cpu_of(rq); + u64 now; if (!dl_task(curr) || !on_dl_rq(dl_se)) return; @@ -1165,7 +1166,8 @@ static void update_curr_dl(struct rq *rq) * natural solution, but the full ramifications of this * approach need further study. */ - delta_exec = rq_clock_task(rq) - curr->se.exec_start; + now = rq_clock_task(rq); + delta_exec = now - curr->se.exec_start; if (unlikely((s64)delta_exec <= 0)) { if (unlikely(dl_se->dl_yielded)) goto throttle; @@ -1178,7 +1180,7 @@ static void update_curr_dl(struct rq *rq) curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); - curr->se.exec_start = rq_clock_task(rq); + curr->se.exec_start = now; cgroup_account_cputime(curr, delta_exec); sched_rt_avg_update(rq, delta_exec);