From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 282CBC1B0F6 for ; Wed, 20 Jun 2018 10:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E24D320836 for ; Wed, 20 Jun 2018 10:18:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E24D320836 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754144AbeFTKSp (ORCPT ); Wed, 20 Jun 2018 06:18:45 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:42057 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752747AbeFTKSn (ORCPT ); Wed, 20 Jun 2018 06:18:43 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07402;MF=xlpang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0T32GEb7_1529489915; Received: from localhost(mailfrom:xlpang@linux.alibaba.com fp:SMTPD_---0T32GEb7_1529489915) by smtp.aliyun-inc.com(127.0.0.1); Wed, 20 Jun 2018 18:18:35 +0800 From: Xunlei Pang To: Peter Zijlstra , Ingo Molnar , Ben Segall Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] sched/fair: Advance global expiration when period timer is restarted Date: Wed, 20 Jun 2018 18:18:34 +0800 Message-Id: <20180620101834.24455-2-xlpang@linux.alibaba.com> X-Mailer: git-send-email 2.14.1.40.g8e62ba1 In-Reply-To: <20180620101834.24455-1-xlpang@linux.alibaba.com> References: <20180620101834.24455-1-xlpang@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When period gets restarted after some idle time, start_cfs_bandwidth() doesn't update the expiration information, expire_cfs_rq_runtime() will see cfs_rq->runtime_expires smaller than rq clock and go to the clock drift logic, wasting needless cpu cycles on the scheduler hot path. Update the global expiration in start_cfs_bandwidth() to avoid frequent expire_cfs_rq_runtime() calls once a new period begins. Signed-off-by: Xunlei Pang --- kernel/sched/fair.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e6bb68d52962..f167aca066cc 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5204,13 +5204,18 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) { + u64 overrun; + lockdep_assert_held(&cfs_b->lock); - if (!cfs_b->period_active) { - cfs_b->period_active = 1; - hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period); - hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED); - } + if (cfs_b->period_active) + return; + + cfs_b->period_active = 1; + overrun = hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period); + cfs_b->runtime_expires += (overrun + 1) * ktime_to_ns(cfs_b->period); + cfs_b->expires_seq++; + hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED); } static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) -- 2.14.1.40.g8e62ba1