From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AC852296BDB; Mon, 11 Aug 2025 16:08:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754928523; cv=none; b=uop4vS9bYmXGnksxVTZZxQA3OGJ5jof1XHKQVceMKP6lO2e4sYgELGVe3zFBFcsMpQ+6spDsbb2fKyXVXxZHw7/wq+w+bZjIV0ApCkQyzM01pfB4srNG4y8o3v101l+76s2szV+AVM6vnD8VwnPlkoR1ATgaDcEKUTVYwUHxz0w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754928523; c=relaxed/simple; bh=iAW1jKNjD0UVSoigxPrR9o3sKwZoev9A1KPjVuJvzAY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=c8+ywQD1eUJuZnIwHhND5MRU/sMe3GTkZnKNc8G+rDiZPvkqngjvN8FD4ItaALPYZB62ZjvKtPOgOySBEYZut9/4w3v7LWsx6uzCpjW3p4c/GvYtVlkt9OSH6e9x12oZkZCxPU5mGZIR4oZwSinZulu1970Cwf3DNYaMuk1zhc0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=C+nOk/Fz; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="C+nOk/Fz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=iA W1jKNjD0UVSoigxPrR9o3sKwZoev9A1KPjVuJvzAY=; b=C+nOk/Fz2j5xcQwo6/ YUGs7VSVwQuhtfQvBjbSasCUfl4XONEMJV9PyRODOJtEzFsB1iXLQJEn6e0xD8Uj CnJWKvvSVqDwB7Vp2cEHEW0kLUWUxcy/vao2Tdi7KssTIYuIj9VPzMf92f/+HTya Lm5g4rdCRdYqmq2jRlBiU/2GQ= Received: from zhaoxin-MS-7E12.. (unknown []) by gzga-smtp-mtada-g0-2 (Coremail) with SMTP id _____wDnftqmFJpoiA8xAw--.21078S2; Tue, 12 Aug 2025 00:04:55 +0800 (CST) From: Xin Zhao To: tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, will@kernel.org, boqun.feng@gmail.com, longman@redhat.com, bigeasy@linutronix.de, clrkwllms@kernel.org Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH] sched/cgroup: Lock optimize for cgroup cpu throttle Date: Tue, 12 Aug 2025 00:04:54 +0800 Message-Id: <20250811160454.884224-1-jackzxcui1989@163.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wDnftqmFJpoiA8xAw--.21078S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7WF4DAr4UArW7uF1fGFW7Arb_yoW8GF13pa yUJr9I9F4kKF13tw18J3yxZ34Fg3s8GrW3GFy8Jrs0ka1qqryF9F13Kr43ua1xCFZxu3WU Xr1Y934DKFnrZaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j8DGOUUUUU= X-CM-SenderInfo: pmdfy650fxxiqzyzqiywtou0bp/1tbioxWmCmiaBhczAwABsI On Mon, 2025-08-11 at 22:18 +0800, Sebastian wrote: > Yeah, please have a look at: > https://lore.kernel.org/lkml/20250715071658.267-1-ziqianlu@bytedance.com/ Dear Valentin, In addition to the information in my previous response to Sebastian, I would like to add the following point as a reason for my self-recommendation (to explore my patch for solving the cgroup performance issue in RT-Linux): RT-Linux is a system that places a high emphasis on real-time performance. The fact that regular tasks are also included in cgroup groups and throttled suggests that they are relatively low-priority tasks that are not expected to interfere with high-priority tasks. Therefore, is it not a bit too late to impose limits only after returning to user mode? Furthermore, when a throttled task is awakened from S or D state, according to the logic of "imposing limits after returning to user mode," it could cause that low-priority task to wake up associated low-priority tasks one after another, leading to a sudden increase in running time, which contradicts the relatively precise CPU usage targets typically required in RT-Linux systems. Additionally, I believe there are still many areas for improvement in my patch, and I hope to bring it to the community to gather suggestions from experts to see if there are areas for iterative improvement. Thanks Xin Zhao