From nobody Wed Dec 17 17:46:44 2025 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 399BC21519B for ; Mon, 9 Dec 2024 09:02:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733734944; cv=none; b=CZpROTbrYcMnEcT+1tooUfDthAfNLHsX7ok1N1xfmZJp8dye1mPgef85lgoD9pRrBpMgyWFEi6pvZeiwp9zO19lO6I0sSeh9UPkd/WqAWoLZRMEC4r1K7qqqm/D3wwSlvyQiI3kZEAGksFBztDiGhdrymEG2VFns3db9RmlJ9KA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733734944; c=relaxed/simple; bh=cf9dyL6/PNkWyw15AxxEcxcYPYFRL47e/VHupH4ZnsI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=Iy10Zelv4E3yh7WifxN9KmWkLisiMm1I+99CRTGGYPyz45JcW6BInq19cjwSnx8u4+jLWgtf0ysxPqOhYkVnwrUigi1dY39/9Orh+dKZJk4z1J2Bb/aSARVk8kO2QbUDcOjO1gP2keklAPptXvB621Tbgr1mgLbApI2/fzNF5Qw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; spf=pass smtp.mailfrom=bytedance.com; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b=SxEbTIul; arc=none smtp.client-ip=209.85.210.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bytedance.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bytedance.com header.i=@bytedance.com header.b="SxEbTIul" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-725dbdf380aso944680b3a.3 for ; Mon, 09 Dec 2024 01:02:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1733734940; x=1734339740; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=JvtR8cnQupCYqwoKVo/nm49rLeqd+grV918TGv1GjgM=; b=SxEbTIulH60KbyzHDvwwLkIt0Z3bS+vuhbJ7G//4vf6baPZ95E4zEHy7xOJJmYWY2d d3LY+Siw88YhxzBji9HngfBR+negPbvVMNCco/ydH9LR4OgZz7CLJOhcPLbD6BeSRoFj NOBOWS6q9mG1u885WfhBOiy0bcpc3gxh5mXpsMeFSH0W5noHqy75ZRx5oOwkbpJMZy5X w6RRPo0/sGmYCqISh+GJzu9zsAZSlEeE9oMQjoI13lyQ5kCS8ZaX26t0HvbV+WIC10YT nOfAo4ZJwK2ubd0u+0t/EBG9ARDYMo4q1rFmtEZyDdWylwOZFdw7j2+Tq2gnX7TCyECs fz2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733734940; x=1734339740; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=JvtR8cnQupCYqwoKVo/nm49rLeqd+grV918TGv1GjgM=; b=hjZSgaA++tDfmAUNrnkXoCe4Mgg671DRVto3G+8EXJYf8o8C6AqgKzgkhEBfSdsfyE 0Ki+aLkheXlCtrLQ1nPvguVx1rxxXHSTeYxrBYz4Cq5Uvzqly3iZCeTImM03qIXCXGHZ OxeGb7olEyi7FIG8NZ3+hRYRHgVG7UCOhnpt1rk7QGU7En0S7rkLSUaElBAljwSBmGGy 9m3SCbJvPUkwZsHYacpcQUASvD6wQSuOGVkWs5l4jpJMyHe7m7P6wynlWn1hWQm4sLIz hY6Dhzl9/ggb7zpF0QvoHCH+8/IXCQs3894seCb/khyktXzuU6ZydlkmGsgTqUccqluJ ZKSQ== X-Forwarded-Encrypted: i=1; AJvYcCXyKBUku1LCVQLXqnP440PknNRPgACw2vkpyqSydbB5PudCvV20r7GnCkcE5+1vn/zZKVEs3JrS5lm20Dg=@vger.kernel.org X-Gm-Message-State: AOJu0Yx2Y7RqfVGK4Qq2fdlbk8xmlC2gyoAZDCB/0f8kv3rXkQoeZZWg lDag/BWxMHX6lWXtp84THhhfty/PwXFJDfkn5erHP1pnYV0v3q2UGdH0qqE603k= X-Gm-Gg: ASbGncsJMI9cEK4mZWANcp/p7KZ/f5x6vjnPUuVaU2D8OfCYLZTeTsQcMYIgMcHDh0/ OeKtqIcP0vCfwnmM/1qK48+LjQmddYkE9f/03RZwyU/qI1Vku48BGDjwESsFmuK5cxHozqRaGzC 1lOSZIbTN7j4bvoiPYcS0PkM+gk7Nckzdy6rHIzFKIsD7MOU71KTwB/FzsRgSIVxrdFZqhStzJQ EIKXih2GZXb4KAFNyRR0X7Bfg2LMmzp7qKiaIN6AQ== X-Google-Smtp-Source: AGHT+IFmpSpcVOn2Hcdd0lYtgr6LtTEm+EytvTlHcDuayCCnQJo3iR47k6Zx7CM/mZBJOkKcJ2SLJQ== X-Received: by 2002:a05:6a00:816:b0:725:eb12:a73b with SMTP id d2e1a72fcca58-725eb12aa1dmr5546999b3a.20.1733734940457; Mon, 09 Dec 2024 01:02:20 -0800 (PST) Received: from 4CE152BDRN.bytedance.net ([203.208.189.11]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-725a29e9003sm7036290b3a.44.2024.12.09.01.02.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Dec 2024 01:02:20 -0800 (PST) From: Vincent Zhou X-Google-Original-From: Vincent Zhou To: peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org Cc: vincentzhou@bytedance.com Subject: [PATCH] sched/rt: fix the error in rt task wait time calculation Date: Mon, 9 Dec 2024 17:02:05 +0800 Message-Id: <20241209090205.2181878-1-vincentzhou@bytedance.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: vincentzhou update_stats_wait_end_rt needs to be called in dequeue_task_rt to update the wait_start variable, otherwise calling update_stats_wait_start_rt again will casue a wrong small value of wait_start because the following codes logic: if (p && likely(wait_start > prev_wait_start)) wait_start -=3D prev_wait_start; After that, update_stats_wait_end_rt is called again, it will calculate wait time by using current rq_clock subtracting wait_start which will cause a very big wait time. Signed-off-by: vincentzhou --- kernel/sched/rt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index bd66a46b06ac..544dd55447df 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1488,6 +1488,10 @@ static bool dequeue_task_rt(struct rq *rq, struct ta= sk_struct *p, int flags) struct sched_rt_entity *rt_se =3D &p->rt; =20 update_curr_rt(rq); + + if (!task_current(rq, p)) + update_stats_wait_end_rt(rt_rq_of_se(rt_se), rt_se); + dequeue_rt_entity(rt_se, flags); =20 dequeue_pushable_task(rq, p); --=20 2.25.1