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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 CY4PEPF0000E9D1.mail.protection.outlook.com (10.167.241.136) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.92.5 via Frontend Transport; Thu, 4 Jun 2026 05:20:53 +0000 Received: from satlexmb07.amd.com (10.181.42.216) 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 15.2.2562.41; Thu, 4 Jun 2026 00:20:52 -0500 Received: from [10.136.33.4] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.41 via Frontend Transport; Thu, 4 Jun 2026 00:20:44 -0500 Message-ID: <0aa0d84c-9d0e-4ca1-9a9c-6370976a0974@amd.com> Date: Thu, 4 Jun 2026 10:50:44 +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 v3 08/20] sched/fair: load balance only among preferred CPUs To: Shrikanth Hegde , , , , , , , CC: , , , , , , , , , , , , , , , , , , , , , , References: <20260514152204.481115-1-sshegde@linux.ibm.com> <20260514152204.481115-9-sshegde@linux.ibm.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260514152204.481115-9-sshegde@linux.ibm.com> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: vQEkX9RkD3VP6fsvlFOxIaGrrcphp/DZ9mjYiOxEV300M8U55BhEmc85WhO0aauLy9+0GsCC076lZcDbaeF9vvAmv/vIM2zYjH1F2mkmtHiwcPvOdG1CbiXhrJWcmfq/b9u5FMvj2hTIQojr0hTRLNoq4ymyEUg1qWJ6q/bulCE8F0RhBxeDeSdxz29BVkmxxZI1+b1sO+m5Kb3r7qpnp/YV1M4yr+DfECfYhbFnvFBcfferPj+snH9WUUuhuSjAvswEDrbaRYoXDet+ZdsbeNEKGMWvR25vUb9Y6ZP4qA1AajwKnzvDAFPvT50ydha0s6XOKjG4KgTs3+jPZE2OvH4wCponN9OYFJ+eo/zyaSTSj8w7fCe/MNLV/mzAUFhZCOpq+RjbVTz7WZw/Q7ia1FPLB1DBo6fwi0FRiazAC9/kYEdJW5Y1tD1DQ34uQBQ9 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Jun 2026 05:20:53.1436 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: fcbdedaa-f1c4-45a0-9952-08dec1f90c66 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: CY4PEPF0000E9D1.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR12MB9409 Hello Shrikanth, On 5/14/2026 8:51 PM, Shrikanth Hegde wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index a704285ac55a..0a851d4b0d7e 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -12087,6 +12087,9 @@ static int sched_balance_rq(int this_cpu, struct rq *this_rq, > > cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask); > > + /* Spread load among preferred CPUs */ > + cpumask_and(cpus, cpus, cpu_preferred_mask); nit. Instead of the onine_mask, can we keep the cpu_preferred_mask closer in sync with the active_mask? That way, if we can ensure that a preferred CPU is always a subset of the active_mask, we can save on a couple of cpumask_and() operations by just looking at preferred_mask instead of both the active_mask and the preferred_mask. Are there any complications in that approach to track it via sched_cpu_activate() / sched_cpu_deactivate()? > + > schedstat_inc(sd->lb_count[idle]); > > redo: -- Thanks and Regards, Prateek