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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 58435C433E7 for ; Thu, 15 Oct 2020 06:49:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0F3121D7F for ; Thu, 15 Oct 2020 06:49:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cFo/XTMd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729172AbgJOGtQ (ORCPT ); Thu, 15 Oct 2020 02:49:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728264AbgJOGtQ (ORCPT ); Thu, 15 Oct 2020 02:49:16 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F348C061755 for ; Wed, 14 Oct 2020 23:49:16 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id e7so1395587pfn.12 for ; Wed, 14 Oct 2020 23:49:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Aj3k1TUx2Xyvn7c5sjrpioU7FRQHTTQ4Isq3jtdMKxQ=; b=cFo/XTMdNV5gvmqI95/qCTwkq+Qc7qhkeWRNCqjy1+mqXj9CQP1ObqTG4Oc8UVWqt8 CwqRDPNn1F82nfDOsgKXTKXzY1XSCRQ+VF5ddS5EtNSfVoHwp7NRemhuRD7Bz31NC3sB 6DbRO36HBhecuW+qt7atEA3Ofnc7tg0RwwVSBjR+LoKSLCMseNa8pSgzwsau9mdT/teE jFwhrEHSGW/DAOZHBlx8kn2clsyRuBaxH161gc7Nt8ul0MqaJJoyLX5sxzXItxf1eyx3 r0JstXls159EYV3d3asJfnB/iVXFT5V/VwpDzBlePnZEbNafgdXfgcALQ++74c3FYIxW xnfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Aj3k1TUx2Xyvn7c5sjrpioU7FRQHTTQ4Isq3jtdMKxQ=; b=VLzZ0RbeoJe0JDt7CUiPNs7BI64ZAbg1MDOuRnsCXJnmwcSYQy16yGrh/0VpUBzuEX 4VBn2d3O12fqKJ2rlqyIjkLNcq/uj9Tszqd9tO81E/xbJ2G57I4M+RhYJnOB/Llm0g/E OAkOP4lWW2DK3U1Zjl8+fyDUcB0WzPsNLktIlSCd1QVwon1zNOw3H7w9RP8oEyGJ6IkU GLL/0A5PTqvdnAcCKluoz2C+QVwst0NFeGa7WsQMXibrsdvXqNDBCN0k3hryNO92Ymhi UeHuLtbQpKppidaekxJGZ9mXNtTaoGW1psm7BWujY39iIbHRhDSgxW871a9m2hY7bmyl ip4g== X-Gm-Message-State: AOAM532r2FefPKTSM4/Z5B65M1pFCzYLLI2A6WOk1K+AfM16L8JWNjHo WoGTpkBq0iJQwu/R6JF4jCp/7YQHaQomqg== X-Google-Smtp-Source: ABdhPJymr58AOo25YBG8RLbjEucbZlnifw45ZKQEFJTbZVIgcDJiz6yXzg9n8IVHtm8OKpiSgHjCAg== X-Received: by 2002:a63:7549:: with SMTP id f9mr2277935pgn.47.1602744555826; Wed, 14 Oct 2020 23:49:15 -0700 (PDT) Received: from localhost.localdomain ([203.100.54.194]) by smtp.gmail.com with ESMTPSA id s187sm2067592pgb.54.2020.10.14.23.49.12 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Oct 2020 23:49:15 -0700 (PDT) From: qianjun.kernel@gmail.com To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org Cc: jun qian , Yafang Shao Subject: [PATCH 1/1] Sched/fair: Improve the accuracy of sched_stat_wait statistics Date: Thu, 15 Oct 2020 14:48:46 +0800 Message-Id: <20201015064846.19809-1-qianjun.kernel@gmail.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: jun qian When the sched_schedstat changes from 0 to 1, some sched se maybe already in the runqueue, the se->statistics.wait_start will be 0. So it will let the (rq_of(cfs_rq)) - se->statistics.wait_start) wrong. We need to avoid this scenario. Signed-off-by: jun qian Reviewed-by: Yafang Shao --- kernel/sched/fair.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1a68a05..6f8ca0c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -906,6 +906,15 @@ static void update_curr_fair(struct rq *rq) if (!schedstat_enabled()) return; + /* + * When the sched_schedstat changes from 0 to 1, some sched se + * maybe already in the runqueue, the se->statistics.wait_start + * will be 0.So it will let the delta wrong. We need to avoid this + * scenario. + */ + if (unlikely(!schedstat_val(se->statistics.wait_start))) + return; + delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start); if (entity_is_task(se)) { -- 1.8.3.1