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=-12.8 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 5581EC433DF for ; Fri, 9 Oct 2020 09:25:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DEAF72227E for ; Fri, 9 Oct 2020 09:25:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RwZHD2nm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731431AbgJIJZz (ORCPT ); Fri, 9 Oct 2020 05:25:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729195AbgJIJZz (ORCPT ); Fri, 9 Oct 2020 05:25:55 -0400 Received: from mail-oi1-x242.google.com (mail-oi1-x242.google.com [IPv6:2607:f8b0:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6567C0613D2 for ; Fri, 9 Oct 2020 02:25:54 -0700 (PDT) Received: by mail-oi1-x242.google.com with SMTP id 16so9509823oix.9 for ; Fri, 09 Oct 2020 02:25:54 -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=cEY5igIwIVqg7iSnPtH8wWYjqyD7WfVBwRYRioZpnzY=; b=RwZHD2nmYM0CAkHF6aaqK82Wk3veVjLE0WevppIlF/xWTlco3XXncKPu8yAtNSJ6rB KBIHPQlHgmefF4fdVcIoZwOshqgr24kGX97wboLn9M6MYyOuH92xuVZq8V3lHR2k9HF8 NQLWQSCgTfYMDPnjsxpPOQLWvt41b8VTHoF3LDlN5pwwpazYBb6j21YawhWPSTXMEj7e rvvP4u+ZlUZSH08j3txOZBvHNmiGFrrKMODNwOZVcQaGIPXd5Fu8CNai2XlwnN1va9Pu CYPvkpU6sG3qXPIVriayAEJb2/KRs69qyXT4wBitdJ+i3Q0twy4LMhaHv98UnzVHdGIM ioFQ== 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=cEY5igIwIVqg7iSnPtH8wWYjqyD7WfVBwRYRioZpnzY=; b=hHl0NkoUh/OGfIR8L6xvHAfrADRwvc9FhC/eLCeQ/Qfi/y9R2sDFr2ThxkhY7fQkaK B2bih5VwDpGgeKUSA4Gd44jsFGRW7DqlCm5eMGdC5pB0QS45eQGMrHmlp81gtnR8eSO5 9/gZ8sMVmoSaCWp3Pud3iXg4ZLiQ3vnvWL53IflWtYFg6JrTIIduy73QAFnWSAxUPJzl KGrAVtOQImphd2dBTHUeBf0Mi9Qf6h4OCTxdlhHEj5EdA7Fltp1xl9T+hdX9tZ547AnD PmhhrjASItNOhfLz0JhwBDsFK5DVrjbge7myOIZ6XjlyQRGp+bPBFyVav4VD0YBh6P/O ypVQ== X-Gm-Message-State: AOAM533TqkIMozC9MW1cQJWMwpOoauOrnqh5KQsInWq10FGyz2OL+TA3 TaVBlXyLmEp4D7HTRfcd+rgQWtUsYs8DbN8Y X-Google-Smtp-Source: ABdhPJyUPOj6EuUGjmiLEXYAr6nTISGruC/rg8r01eyiHtG3MpflzIeCa/jOCUpN/xycGnfFC02aTA== X-Received: by 2002:aca:c586:: with SMTP id v128mr1899090oif.115.1602235554201; Fri, 09 Oct 2020 02:25:54 -0700 (PDT) Received: from localhost.localdomain ([50.236.19.102]) by smtp.gmail.com with ESMTPSA id g124sm7026337oia.58.2020.10.09.02.25.48 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Oct 2020 02:25:53 -0700 (PDT) From: qianjun.kernel@gmail.com To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org Cc: linux-kernel@vger.kernel.org, jun qian , Yafang Shao Subject: [PATCH 1/1] Sched/fair: Improve the accuracy of sched_stat_wait statistics Date: Fri, 9 Oct 2020 17:25:30 +0800 Message-Id: <20201009092530.223-1-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 Signed-off-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