From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (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 CEC7A76C85; Wed, 31 Jan 2024 12:32:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706704348; cv=none; b=D5WnpQCoAv3/sPp5Df7W5dsoNQtnVaEUyDlepSQqaXD0jegJ0Vbze1J/uasDde36Fxux2ap7VYFpHRQZWqkT5VuKJr7zosAeK7Z0dd0QuBShaOcKB+bKDz2RQ+ALzlBSf1Z073c9dwaIVGuoBPQfU+SmNpiw+xpSlqNrg5EBPWk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706704348; c=relaxed/simple; bh=FED9EEmMKE+UuTS+51bHGBf+zW3QlM2itO24OOhtWuk=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=oNSW1IpgENX0jgw1+sZyEXgq6xm7rDY4WIwNhOX/vRr/MF4IfSfjltzkEkxko/DRvAL7zXp5s0VF3cIHx4DRqS0u0bR3E4sMyr98qwoUl1lo5wg/scVsSZfTcUfZnuOCeSbGYNooUAwaEr6dBizLw7Fc8xbo51o9KGDSQ9m8I7o= 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=45.249.212.35 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 [172.19.163.44]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4TQ1bC3Zwsz1Q89B; Wed, 31 Jan 2024 20:30:31 +0800 (CST) Received: from dggpeml500018.china.huawei.com (unknown [7.185.36.186]) by mail.maildlp.com (Postfix) with ESMTPS id 580C01404F7; Wed, 31 Jan 2024 20:32:22 +0800 (CST) Received: from octopus.huawei.com (10.67.174.191) by dggpeml500018.china.huawei.com (7.185.36.186) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Wed, 31 Jan 2024 20:32:22 +0800 From: Zhang Qiao To: CC: , , , , Subject: [PATCH] sched/Documentation: Add RT_RUNTIME_SHARE documentation Date: Wed, 31 Jan 2024 20:32:38 +0800 Message-ID: <20240131123238.2332064-1-zhangqiao22@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpeml500018.china.huawei.com (7.185.36.186) RT_RUNTIME_SHARE is an important strategy for rt bandwidth, and we should document this sched feature. Signed-off-by: Zhang Qiao --- Documentation/scheduler/sched-rt-group.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst index d685609ed3d7..4d8eceb71f5e 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 +147,16 @@ 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 borrows rt-runtime from other cpus if it runs +out of its own rt-runtime. + +With this feature enabled, a rt-task probably hits 100% cpu usage and starves +per-cpu tasks like kworkers, as a result, it may hang up the whole system. +Therefore, in order to avoid such exception, recommand to disable this feature +by default unless you really know what you're up to. 3. Future plans =============== -- 2.18.0.huawei.25