From nobody Tue Dec 16 16:38:42 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 429921A23AF; Wed, 5 Mar 2025 04:13:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741147989; cv=none; b=g2kIwV+Q5pyHqJl+0bB8WdcCKF8/YqmC07oxTv7UsyTW0g1xEX3/FlvCgu/aM6fkLUHfAwnhnR+bVd5ZwcECMifFC4IxXX5ctmk1HiLlkS1pyez3V5TQGYaCTKVbUVjIUE5HJuJZGlzQesARWHTCV+/QNN/u59X2bHl3mtzpFZY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741147989; c=relaxed/simple; bh=RBsh/xDj4vd4BAKgWWaorA7r/mUYNpFPasyRXkkSQEg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WiLyGbHa49sOqM6SjM6KTglClI3u6mChQzKdbrZbbYCs90O3nDmtWGBypkN5U5IISAQbsXYFlxkV74Fo+fshvU5ELMk/8G7mf8WRPzcoEoGO/JmDew4utj2BUTe35IFQddRTAzXghhOnmXbYmBtyw4lRWWOgjBMzbgaMyKO9N8U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=COvuuk+S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="COvuuk+S" Received: by smtp.kernel.org (Postfix) with ESMTPS id C129FC4CEEB; Wed, 5 Mar 2025 04:13:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741147988; bh=RBsh/xDj4vd4BAKgWWaorA7r/mUYNpFPasyRXkkSQEg=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=COvuuk+ShgIppQ6Ihy1TUO9D39jQ3ibKNx+bE9FsBoqL980OPhD1D1WTp3pmi4+OZ 3FuFgn7nTTPBiboTaxvRR23TZN5tCxba+H5EGb+CtdO3SiiA5adNfoFFnFX2Xf1EyR JNaLAXP18n3FYPxNj+ozt3hXUKvvPMplWITGYT6qTsQnYu86C0uc+VL2BmReakb4RM F52IkM3dJcpyl354lM5nf/I3muacTjwaXRFJkpt8eLmcOWYAik7cbvdsz7i++6lWPg fn2uId5LhUaMmXQPZjJ1YVcCKdPj2/XufF7Gk5VVdIpFegZC0JQC24XHzdJC882hh6 wDXEY0Y+RdvFA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADC62C282DE; Wed, 5 Mar 2025 04:13:08 +0000 (UTC) From: Shashank Balaji via B4 Relay Date: Wed, 05 Mar 2025 13:12:44 +0900 Subject: [PATCH 2/2] cgroup, docs: Document interaction of RT processes with cpu controller Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250305-rt-and-cpu-controller-doc-v1-2-7b6a6f5ff43d@sony.com> References: <20250305-rt-and-cpu-controller-doc-v1-0-7b6a6f5ff43d@sony.com> In-Reply-To: <20250305-rt-and-cpu-controller-doc-v1-0-7b6a6f5ff43d@sony.com> To: Tejun Heo , Johannes Weiner , =?utf-8?q?Michal_Koutn=C3=BD?= , Jonathan Corbet Cc: Waiman Long , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Shinya Takumi , Shashank Balaji X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=3070; i=shashank.mahadasyam@sony.com; h=from:subject:message-id; bh=C7JgnbF46KXkV/sLIdJxl+OtmX2NjXxlaJ2fLtetvIs=; b=owGbwMvMwCV2mPH4Ij++H1mMp9WSGNKPnw9e//2RmAhj3o5Du+SOLT0Xfi9vQYeCx84HZxYwC vzvemXwu6OUhUGMi0FWTJHlncy6CwetLJu+Hmf4BjOHlQlkCAMXpwBMxG8VI0NzIlvCn5hrrx4x iPRL7MhbL7J4AZ+BcWTx1e7fikX8J2Yz/A9+WhAhdXtX9QvT+uPMHMKiUusO/G6y/eXmc2Ptv5X Xv7EDAA== X-Developer-Key: i=shashank.mahadasyam@sony.com; a=openpgp; fpr=EE1CAED0C13A3982F5C700F6C301C7A24E0EF86A X-Endpoint-Received: by B4 Relay for shashank.mahadasyam@sony.com/default with auth_id=354 X-Original-From: Shashank Balaji Reply-To: shashank.mahadasyam@sony.com From: Shashank Balaji If the cpu controller is enabled in a CONFIG_RT_GROUP_SCHED disabled setting, cpu.stat and cpu.pressure account for realtime processes, and cpu.uclamp.{min, max} affect realtime processes as well. None of the other interface files are affected by or affect realtime processes. Signed-off-by: Shashank Balaji --- Documentation/admin-guide/cgroup-v2.rst | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-= guide/cgroup-v2.rst index f293a13b42ed69e7c6bf5e974cb86e228411af4e..2c267f42e5fef9c4e2c3530ce73= 330d680b9b2dc 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1095,7 +1095,9 @@ realtime processes irrespective of CONFIG_RT_GROUP_SC= HED. CPU Interface Files ~~~~~~~~~~~~~~~~~~~ =20 -All time durations are in microseconds. +All time durations are in microseconds. Only cpu.stat and cpu.pressure acc= ount +for realtime processes, and only cpu.uclamp.min and cpu.uclamp.max +affect realtime processes. =20 cpu.stat A read-only flat-keyed file. @@ -1115,6 +1117,9 @@ All time durations are in microseconds. - nr_bursts - burst_usec =20 + The runtime of realtime processes is accounted for only by the usage_u= sec, + user_usec, and system_usec fields. + cpu.weight A read-write single value file which exists on non-root cgroups. The default is "100". @@ -1158,8 +1163,9 @@ All time durations are in microseconds. cpu.pressure A read-write nested-keyed file. =20 - Shows pressure stall information for CPU. See - :ref:`Documentation/accounting/psi.rst ` for details. + Shows pressure stall information for CPU, including the contribution of + realtime processes. See :ref:`Documentation/accounting/psi.rst ` + for details. =20 cpu.uclamp.min A read-write single value file which exists on non-root cgroups. @@ -1170,7 +1176,8 @@ All time durations are in microseconds. =20 This interface allows reading and setting minimum utilization clamp values similar to the sched_setattr(2). This minimum utilization - value is used to clamp the task specific minimum utilization clamp. + value is used to clamp the task specific minimum utilization clamp, + including those of realtime processes. =20 The requested minimum utilization (protection) is always capped by the current value for the maximum utilization (limit), i.e. @@ -1185,7 +1192,8 @@ All time durations are in microseconds. =20 This interface allows reading and setting maximum utilization clamp values similar to the sched_setattr(2). This maximum utilization - value is used to clamp the task specific maximum utilization clamp. + value is used to clamp the task specific maximum utilization clamp, + including those of realtime processes. =20 cpu.idle A read-write single value file which exists on non-root cgroups. --=20 2.43.0