From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E155D39863 for ; Tue, 16 Apr 2024 07:13:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.191 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713251587; cv=none; b=htveLRT71ic41OezoGJU5zSsEB11rO6BRNxU4myTYJRoHdsLORAU8klDkL0F7gUO23jqA5p+fR01cWK+4KlWRlb40AsmyvqSDmVP1QmtUCBGpbP+jxTg50rG+0s30wm2RZuTBKcmu/ivqUvBmTP9Ak90FgRir6S3bBVVrquBwcc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713251587; c=relaxed/simple; bh=wdBCqomTv0Itl5wccY1fTUKRkBSjyLIkCcSkicbtDcs=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=A9hlPv1K5f3t0QMqACbN6hmghu3x3coIeY7qBqqZg1ACA9dBK2aggahYvQ+YS/p8E1efpUd++K1Pt0ebNfljwbVStiCtep5DjdUqfWEsPM63Y57OBZ3uswQSa/i77WUAt9Hb7JEBeaJzQkcWTWvtqJVblFaH6rh0KZPBmbYlyMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.191 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4VJZwm5Phnz1GGjC; Tue, 16 Apr 2024 15:12:08 +0800 (CST) Received: from canpemm500001.china.huawei.com (unknown [7.192.104.163]) by mail.maildlp.com (Postfix) with ESMTPS id 3B0561A016F; Tue, 16 Apr 2024 15:13:01 +0800 (CST) Received: from [10.67.111.186] (10.67.111.186) by canpemm500001.china.huawei.com (7.192.104.163) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Tue, 16 Apr 2024 15:13:00 +0800 Message-ID: Date: Tue, 16 Apr 2024 15:13:00 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.1.1 Subject: Re: [PATCH] sched: Improve the accuracy of sched_stat_wait statistics for rt and dl To: , , , , , , , , , CC: , , References: <20240322081521.2687856-1-zhangqiao22@huawei.com> From: Zhang Qiao In-Reply-To: <20240322081521.2687856-1-zhangqiao22@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500001.china.huawei.com (7.192.104.163) ping. 在 2024/3/22 16:15, Zhang Qiao 写道: > Where commit b9c88f752268 ("sched/fair: Improve the accuracy of > sched_stat_wait statistics") fixed a wrong scenairio for cfs schedstat. > > This wrong scenario is also present for the RT task. For avoiding this > scenario, add wait_start check in __update_stats_wait_end(); > > Signed-off-by: Zhang Qiao > --- > kernel/sched/fair.c | 9 --------- > kernel/sched/stats.c | 11 ++++++++++- > 2 files changed, 10 insertions(+), 10 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 6a16129f9a5c..36c81fe0086b 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1208,15 +1208,6 @@ update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se) > > stats = __schedstats_from_se(se); > > - /* > - * 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(stats->wait_start))) > - return; > - > if (entity_is_task(se)) > p = task_of(se); > > diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c > index 857f837f52cb..7077eb490c09 100644 > --- a/kernel/sched/stats.c > +++ b/kernel/sched/stats.c > @@ -20,8 +20,17 @@ void __update_stats_wait_start(struct rq *rq, struct task_struct *p, > void __update_stats_wait_end(struct rq *rq, struct task_struct *p, > struct sched_statistics *stats) > { > - u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start); > + u64 delta; > > + /* > + * When the sched_schedstat changes from 0 to 1, some sched se > + * maybe already in the runqueue, the stats->wait_start will be 0. > + * So it will let the delta wrong. We need to avoid this scenario. > + */ > + if (unlikely(!schedstat_val(stats->wait_start))) > + return; > + > + delta = rq_clock(rq) - schedstat_val(stats->wait_start); > if (p) { > if (task_on_rq_migrating(p)) { > /* >