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Tue, 7 Oct 2025 01:30:01 +0000 From: Aaron Tomlin To: gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org Cc: riel@surriel.com, frederic@kernel.org, atomlin@atomlin.com, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/1] tick/nohz: Expose housekeeping CPUs in sysfs Date: Mon, 6 Oct 2025 21:29:57 -0400 Message-ID: <20251007012958.16666-1-atomlin@atomlin.com> X-Mailer: git-send-email 2.49.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: BL1PR13CA0284.namprd13.prod.outlook.com (2603:10b6:208:2bc::19) To CWLP123MB3523.GBRP123.PROD.OUTLOOK.COM (2603:10a6:400:70::10) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CWLP123MB3523:EE_|LOBP123MB8319:EE_ X-MS-Office365-Filtering-Correlation-Id: ed16e9c8-5367-4b33-3972-08de054108ce X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|366016; 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This provides userspace performance tuning tools and resource managers with a canonical, reliable method to accurately identify the cores responsible for essential kernel maintenance workloads (RCU, timer callbacks, and unbound workqueues). Currently, tooling must manually calculate the housekeeping set by parsing complex kernel boot parameters (like isolcpus= and nohz_full=) and system topology, which is prone to error. This dedicated file simplifies the configuration of low-latency workloads. Changes since v1 [1]: - Refactor to use an if statement (Greg KH) - Use DEVICE_ATTR_RO() instead (Greg KH) - Document the new file under Documentation/ABI (Greg KH) [1]: https://lore.kernel.org/lkml/20251006005853.76335-1-atomlin@atomlin.com/ Aaron Tomlin (1): tick/nohz: Expose housekeeping CPUs in sysfs .../ABI/testing/sysfs-devices-system-cpu | 11 +++++++++++ drivers/base/cpu.c | 15 +++++++++++++++ 2 files changed, 26 insertions(+) -- 2.49.0