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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by CH1PEPF0000AD7D.mail.protection.outlook.com (10.167.244.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9564.3 via Frontend Transport; Tue, 27 Jan 2026 06:30:53 +0000 Received: from satlexmb10.amd.com (10.181.42.219) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Tue, 27 Jan 2026 00:30:53 -0600 Received: from satlexmb07.amd.com (10.181.42.216) by satlexmb10.amd.com (10.181.42.219) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Tue, 27 Jan 2026 00:30:52 -0600 Received: from [10.136.38.16] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Mon, 26 Jan 2026 22:30:49 -0800 Message-ID: <306a53a5-0b99-4e5a-810b-5aa4e86a72d1@amd.com> Date: Tue, 27 Jan 2026 12:00:48 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6] sched/clock: Avoid false sharing for sched_clock_irqtime To: Wangyang Guo , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider CC: , Shrikanth Hegde , Benjamin Lei , Tim Chen , Tianyou Li References: <20260127044159.2254247-1-wangyang.guo@intel.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260127044159.2254247-1-wangyang.guo@intel.com> Content-Type: text/plain; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Jan 2026 06:30:53.3732 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f5fdc1d5-84d5-4000-53bc-08de5d6d9f0b X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CH1PEPF0000AD7D.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY3PR12MB9704 Hello Wangyang, On 1/27/2026 10:11 AM, Wangyang Guo wrote: > --- a/kernel/sched/clock.c > +++ b/kernel/sched/clock.c > @@ -173,6 +173,7 @@ notrace static void __sched_clock_work(struct work_struct *work) > scd->tick_gtod, __gtod_offset, > scd->tick_raw, __sched_clock_offset); > > + disable_sched_clock_irqtime(); We can come here with !irqtime_enabled() but this is a slowpath so I don't really mind calling disable_sched_clock_irqtime() unconditionally here. Feel free to include: Reviewed-by: K Prateek Nayak Tested-by: K Prateek Nayak Tested with a bunch of fake cases of sched_clock going unstable by hacking the kernel and the irqtime was disabled correctly in both cases - pre-lateinit and post-lateinit. > static_branch_disable(&__sched_clock_stable); > } > -- Thanks and Regards, Prateek