From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) (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 2F257DDA5; Mon, 27 May 2024 03:13:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716779623; cv=none; b=UPzdkhbg8wk67UP4AR2UlOvTi/16YR9+48w1wjBoW4qupDa/Nu7rPlalbcXMoYyFzdDlW/7lk+IszYtKiuBj2pavtU2V0kklW3gxnh+xHZ64moau0ZeeKX5Kq92NIi2EGOB898GOJ2Yhcefs0a9+nMjv8KkI90EFf/t+ErgE0g4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716779623; c=relaxed/simple; bh=LQUBKtXo9O7lpjMOTq/te/3KdZL8KecWHRgyfxXZNM4=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=bCmDZSbGuQCjOnF1AWfNFf8a8biBCSpAF0qirML7JHeIMR/LHwAcWqaKE+NnuEgvgFCAojlZ8d0EdcLLdICECtfRh3XoV8EOR41GoOD+rjcAwvS3wz6q1WTzeWHfd4bUSbotpnurqnU/Ep4aRRWLpWky6wFELExX20rCn2R9YGk= 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=45.249.212.189 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 [172.19.163.174]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Vngcw5MNvzPn51; Mon, 27 May 2024 11:10:24 +0800 (CST) Received: from canpemm500001.china.huawei.com (unknown [7.192.104.163]) by mail.maildlp.com (Postfix) with ESMTPS id F0371140384; Mon, 27 May 2024 11:13:31 +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 15.1.2507.39; Mon, 27 May 2024 11:13:31 +0800 Message-ID: <3dffcc67-750e-c4c4-9154-99f1b1154fe0@huawei.com> Date: Mon, 27 May 2024 11:13:31 +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 v2] sched/Documentation: Add RT_RUNTIME_SHARE documentation To: , , , , CC: , References: <20240419090432.1935211-1-zhangqiao22@huawei.com> From: Zhang Qiao In-Reply-To: <20240419090432.1935211-1-zhangqiao22@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500001.china.huawei.com (7.192.104.163) Ping. 在 2024/4/19 17:04, Zhang Qiao 写道: > RT_RUNTIME_SHARE is an important strategy for rt bandwidth, and > we should document this sched feature. > > Signed-off-by: Zhang Qiao > Improvements-suggested-by: Bagas Sanjaya > --- > Documentation/scheduler/sched-rt-group.rst | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst > index d685609ed3d7..eea2fc6f068f 100644 > --- a/Documentation/scheduler/sched-rt-group.rst > +++ b/Documentation/scheduler/sched-rt-group.rst > @@ -12,6 +12,7 @@ Real-Time group scheduling > 2.1 System-wide settings > 2.2 Default behaviour > 2.3 Basis for grouping tasks > + 2.4 RT_RUNTIME_SHARE sched feature > 3. Future plans > > > @@ -146,6 +147,17 @@ For now, this can be simplified to just the following (but see Future plans): > > \Sum_{i} runtime_{i} <= global_runtime > > +2.4 RT_RUNTIME_SHARE sched feature > +---------------------------------- > + > +RT_RUNTIME_SHARE allows a cpu to borrow rt-runtime from other cpus if it runs > +out of its own rt-runtime. > + > +With this feature enabled, a rt-task may hit 100% cpu usage and can stall other > +per-cpu tasks like kworkers, as a result, which leads into system hang. > + > +Thus, it is advised to disable this feature by default to avoid aforementioned > +issue unless you know what you're doing. > > 3. Future plans > =============== >