From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (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 276122D2388 for ; Wed, 10 Dec 2025 23:50:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.13 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765410660; cv=fail; b=CN6ZfeEMRK3Uk+USrOOVnjTdFUd2XHxYmzpn7sMpiP4jOFY2o5LhTDS4El6irq3DIl90RjKjxZUlrbWE4vrR+AulsaSCa0/JKiDgJ7Y5GAwIRd29isDwoLSI+PLYAvlDaCAGoAlWlhXBWoMbxFBmXTD1yUtA1bLVQUWoGOEHShE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765410660; c=relaxed/simple; bh=9QbdX0nG+GRg2Fksu/p7rD3BmniNKoRoooA9LfyoRDE=; h=Message-ID:Date:Subject:To:CC:References:From:In-Reply-To: Content-Type:MIME-Version; b=cmkEwxVlkkSCWhl8kAoIVUeBTX3jLnr+JRx9PcBU69GWuEHnVjunQE+M2PLzghGLOUjZPQcI8WFW9RKq0zAA/s6wP9i1WBlsxmUPuNQeC/TlFjR8gCswVBYLSjjZFlJykKuDCzFY3Rgveaq0xJpJSsz6Duls8cnlnrXfpsWTNzc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Df6YWhcw; arc=fail smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Df6YWhcw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1765410658; x=1796946658; h=message-id:date:subject:to:cc:references:from: in-reply-to:content-transfer-encoding:mime-version; bh=9QbdX0nG+GRg2Fksu/p7rD3BmniNKoRoooA9LfyoRDE=; b=Df6YWhcwIOseUML6ezUkbijcfF8hiFQdljV1kn8gwz/JUnoeCI+qdvTQ 6lrBrhYH03ob2xSqn22/+Zo/RANAdJqH4ej3car7x6FAr6XqqZH6xUXf/ cORaROhQFoNbLBmGWvaYMNyOdtp6hGzLe8/KjKb6HQSSmoThc/GCQZZpT NtP/aYei1NPYSClO303T3aHRxVdccap13aD838P0D2S4uAu/I0urSV1NV 9PCpXsdZuj+zC+NHiMtVJnGn0KEfG3CMIgV/bHS2N1X6JRITh15VqaIUi Lhgfi4IAuiJ3j1KNxtnD/YbunnBZRq+Oi67py/GuqyWCCl5uRz+uuEp9J A==; X-CSE-ConnectionGUID: B+Y6W1ZIR76nhfBFpuU/1w== X-CSE-MsgGUID: jIPSJ0AoQniQGihXWY3JYw== X-IronPort-AV: E=McAfee;i="6800,10657,11638"; a="78502128" X-IronPort-AV: E=Sophos;i="6.20,265,1758610800"; d="scan'208";a="78502128" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Dec 2025 15:50:56 -0800 X-CSE-ConnectionGUID: jbYK6MS3T+ue4cX8Vi59Xw== X-CSE-MsgGUID: 4iVC0GUhSuSpe+Su2oHJvQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,265,1758610800"; d="scan'208";a="200809638" Received: from orsmsx903.amr.corp.intel.com ([10.22.229.25]) by orviesa003.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Dec 2025 15:50:57 -0800 Received: from ORSMSX902.amr.corp.intel.com (10.22.229.24) by ORSMSX903.amr.corp.intel.com (10.22.229.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Wed, 10 Dec 2025 15:50:56 -0800 Received: from ORSEDG902.ED.cps.intel.com (10.7.248.12) by ORSMSX902.amr.corp.intel.com (10.22.229.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29 via Frontend Transport; Wed, 10 Dec 2025 15:50:56 -0800 Received: from BL0PR03CU003.outbound.protection.outlook.com (52.101.53.52) by edgegateway.intel.com (134.134.137.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Wed, 10 Dec 2025 15:50:55 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BFkluJbDHvqROFVs0jx2nuTqQDsVgcBVxXlol8lktF8D+5cIQYVIuOrncDBk1rsFMvyQwTrxLPHAg8pAblaNPS70jaS7sfKJH5j+HoYL7SDi3X81n5aaqNQmc502OqappjGbdvbiMKdYNinMzUB1ZZ3W3P0wrQ4MCmOeRg6V/3Zo4NrgIAE9PUh6ysfIBrtbloIeprdKMSYSO1oifHB80uBoPnT1IEcQgZylPWUI41RkgHNfSvm/NaBbsq56xIaK8pEaipuL5b8NsVSHd9LVWSITYLWtnHJ0C6XQRzpr9yQ6JUqzLlZ2P1zFpZr83wzteW/I6TP0C7cu+ad62Wt0VA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=kgtqRAk7RX1y3XUWj0/wN4MFpesLm9T/XhUlI+qicE0=; b=FLS8gYAuee6SMA27EewPuCvt1n9R784OkPXJPMlCFO53Nz7TrJkfbX06YTlum3FG4YZC0AF3Ym8EhEmIMHsYtQ6Fscky9yX6++0UuRgr8a4hsXs7TuoTB0Smgym8+yjx6442VxFcxMIW1ekXtX1Aht3DlXi8/GF27L8dNHlEDvSpFDcDWa1VHuW6xHLpcpD/TOme1iOLbI0JxqAcFD1OBMD6Zil0jl0bBnRpwFFKXcOvScjcVRFRzLWwq+8kojp/JfOh0cHLuR/gepI6caR1zJahqIDpWbs5rF767jF9N/rj6JrJvPTOvtfn7WFMBjT0I7mpeBYWrrvwrf7R3mhr+A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) by MN6PR11MB8104.namprd11.prod.outlook.com (2603:10b6:208:46c::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9412.6; Wed, 10 Dec 2025 23:50:48 +0000 Received: from DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::4af6:d44e:b6b0:fdce]) by DM4PR11MB6020.namprd11.prod.outlook.com ([fe80::4af6:d44e:b6b0:fdce%4]) with mapi id 15.20.9412.005; Wed, 10 Dec 2025 23:50:47 +0000 Message-ID: Date: Thu, 11 Dec 2025 08:50:38 +0900 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 09/23] sched/cache: Count tasks prefering destination LLC in a sched group To: Peter Zijlstra CC: Tim Chen , Ingo Molnar , "K Prateek Nayak" , "Gautham R . Shenoy" , Vincent Guittot , "Juri Lelli" , Dietmar Eggemann , Steven Rostedt , Ben Segall , "Mel Gorman" , Valentin Schneider , "Madadi Vineeth Reddy" , Hillf Danton , Shrikanth Hegde , Jianyong Wu , Yangyu Chen , Tingyin Duan , Vern Hao , Vern Hao , Len Brown , Aubrey Li , Zhao Liu , Chen Yu , Adam Li , Aaron Lu , Tim Chen , References: <1eb6a231ec82b37483208983f0cf10eec823ec9d.1764801860.git.tim.c.chen@linux.intel.com> <20251210125233.GT3707891@noisy.programming.kicks-ass.net> <5613f6eb-7319-464e-9723-2d82ddaca0c9@intel.com> <20251210151621.GM3707837@noisy.programming.kicks-ass.net> Content-Language: en-US From: "Chen, Yu C" In-Reply-To: <20251210151621.GM3707837@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: TYCP286CA0001.JPNP286.PROD.OUTLOOK.COM (2603:1096:400:26c::7) To DM4PR11MB6020.namprd11.prod.outlook.com (2603:10b6:8:61::19) 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: DM4PR11MB6020:EE_|MN6PR11MB8104:EE_ X-MS-Office365-Filtering-Correlation-Id: c0f0d35f-6036-45d8-84da-08de3846f108 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|1800799024|7416014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?ekE0Q1V1YVJKMjlpdTNSS2duK0ZYcmw3cGNIbm1nSW42L05GZWRxTXVpTXlR?= =?utf-8?B?dE5RN281ZDIrd3kwZVJrWXBSaSswMjhjVlFFL2ZjMm43UjhGTUhodEp4TlZH?= =?utf-8?B?K1ZxbEs3UmhJTlpMZGNaTEZ4N2ViclpHbHhjdmh6M0Jnc1BjNnBBSk9XNTdL?= =?utf-8?B?RWFKN0w4WHRNRkNkeWwrcWZFZnZITVZoV05qMlE0eXBoSWVtOUl1UExSUWZy?= =?utf-8?B?K1VMYTFiVUFEVVFwMVFCREZtQUxRaWRLUDZIZGRieDFWT29XWm1uOUFvTGF1?= =?utf-8?B?UXBWbEhIekV4d1B6VG9GMGtGT0xqTDVIUVFtRFhqZWpLeTR3bG9QTVZ5RStq?= =?utf-8?B?RXdoN1ZTUHlEQ3gxVy9yMlNhc1Y0Qk5DSGY2bXhUdWF0ck9LNUppK0tVK0h3?= =?utf-8?B?RVJhVVpGMGlqMVg1cW14dWt0Y0xGZ1p4aGtnMW1nSkZMb2wwZmFaMDE3aXl1?= =?utf-8?B?TEdEYWJBbG5jZFlWN2VlY0xTVFlzWlB6R2kxWkJHL0FFQmRLL0Q2Y2E2Vkpu?= =?utf-8?B?ZlJKT3BweFpmZWxzeEhuVkVOdWIraUpnNFJENDkrdjJQSm5xRy9La0JEUmVD?= =?utf-8?B?Ukh3RS9MSUFoM1U3R0RLTzQ2YUV1VU5wSzkrV0JoRzFLRHlrY3BvWk8rQ05E?= =?utf-8?B?N0FaU21UOGtyWFAxWG1WQWRHSU1VME5RYjB3ek4zc0J0ZHNzZUpkY2NvWnRV?= =?utf-8?B?Q0Vma09MTms3ZlNzQ1Mrd011MzVHdFJSdUdoaEMxNUkrSEJDNVZKa0ZkQ2t4?= =?utf-8?B?NlRNOEU4cFJ4dkU0UWlzaW03TUU1d1MrZzg0aDdCOE9HN09KdFNuZXBaYzRR?= =?utf-8?B?NHM2QXkrVlVlN3hCMUpLcjlPNUhVc3ZIMXlnWW12cFVjeTg2RkI2cklsRDFF?= =?utf-8?B?YkcxYUtsN2w1bVBtOFhvRUx4Q1FBaGwzZUwzaUlYMXdzV0NyMGNMbnl5S0Rz?= =?utf-8?B?OTJxNTN6RDNsSHJDWmxIdVBUVVNheDlEaWJYOFI1OEdPZzFoVnM3Mms3cGdp?= =?utf-8?B?WStMSzU1Y08yeTV4ekV6T2o3ellHUDhQRVRmOG1uUllmbTdVUHZIc0h0MFl5?= =?utf-8?B?cTc1VGludjkzQWxiWXJHT2ZTZHhoZTl4TG5sRzJ2RDFRUXIzSUVhZzE1eW1Y?= =?utf-8?B?MlJXZTFEck81S2NaTEZsSDVTcVVrZHZKUDBjNEorMVdhb004blZkRWIxTDUr?= =?utf-8?B?RzdVZjB6NlVGaXR3SU1lb2xPMW5IQVo3cUZoYjdTYi80biszWlV0bGJ1VlR1?= =?utf-8?B?VENtYnFKb29INy85RkI5eEltbmhySjVuL1llaGsvQnZDZCtVTEcvMjQ2NVJB?= =?utf-8?B?OCsyeDF5YjdMUE5JRnRtaXcxZ0NUUlB5SzlVdmlkZVJ0K1ZxNSthd1BNbmVs?= =?utf-8?B?Ky9ONDQ4Q3FCeXpKZGNNYm5DSlJFTUNoaTQvY2xkcUFQb3FyUklDei9hcmpi?= =?utf-8?B?eHNHeWcyYTNibzBiVzAzNGZKcGs4d3hYNEVHRXJZbnB0ZVNkNzVHY0tqUXRv?= =?utf-8?B?ZWNDYnZ6L2dRalNXbThPcXhScVJCY0NlK2pMc2c5SnI0V3Q2SG1md3JYQXpu?= =?utf-8?B?U3d3T2Z3K25ZMGdobGFXUExicmtPbS83RTE2dXRmeHQrdXgxRG5pbzFBOUFR?= =?utf-8?B?UVVPUUFwYUFoVWlCaVlDRHpnNzhvQlBMT2g4VDFscVI3eVc0dkFXSlRCSW9v?= =?utf-8?B?bGhyRFAwRklsRkNQSkZ3QlJvSGZ4WjQ3aUI2MjhDQytSVVZzNW5IMjFrWk8y?= =?utf-8?B?Z0t3dTFFTTc5bS8wRVpXMGpMSUwyRnRPRlFKYmsybjNjZ0tuSEVodG8vc21t?= =?utf-8?B?SnRMYXJYVjhUbU1nU0NaSXpFM0FLV3BvQXFiaTZFZGxmNXJxWGVXa1cvTGNN?= =?utf-8?B?WkxSMFdiS1pZVnAwdVdBSElIRE50Sm9LOHQxZUJuR1JXU1NyZHE2bUl2SjR3?= =?utf-8?Q?Lfg8w3z2LqyGYKXSGgLJbiiej6xfwkzI?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR11MB6020.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(1800799024)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?aTFDeEdIak1LS0xoZkQ5VmNCTjJQSXZiMER6R21xMFBIY1BwU3NhK3ZVM0t6?= =?utf-8?B?bU44bk9zUXpkWGpWcmlLNGlHbmUxNHJtMUFyK3dZQkZ0U083d1NuUWFHUzha?= =?utf-8?B?TnZZVlNONVJQWW5MaG5HQUdpeWlHQnIrY3dqa2M3OThzSlhrNHhwckxDamNm?= =?utf-8?B?ekJuK2h4Zml6SFl6UkdWWnFnNlFoU0lqbDZsYll6L21vL1owbmlZZ0JOMnlr?= =?utf-8?B?K2xWckRPclo1VXhXQnpNdCtwNjNUcHpETU16Q2o0dkNya2FiUk5kUlVvRjBy?= =?utf-8?B?S3lSckhNb0hTTi9MNVh6UEozaTV5T0tJaGdhSTRYRGQwcndyMTZTaWFETjQ0?= =?utf-8?B?cDR0ZFFNS3ZhTlovRzhYRTlzYmt3azlocVpVZUs0UWtlU09CbFpWTllqUEsx?= =?utf-8?B?aG00VUZTZVo1ZHBmbm9rbEovcnhPV1dxNFdrM3NULzFYMXBUTkI5OU00Kytl?= =?utf-8?B?MjZiM2VXMnJxbUEyeEw0V1dsbTFrZjgxUGNmdEZkMzlML0RhZHRsclM2QzB3?= =?utf-8?B?Nmg4K1k2Yk5vM1RJNG9pMHcyL2xNREFHMHRRZUgweXB3a1ZFMW9wakJWQkJu?= =?utf-8?B?S0k5Ykg0ekxtdGxuNHlGMStEUEZ3dkxtQ29KV3dJTGU2WkdJcmxkYXVHSHVy?= =?utf-8?B?RTVYMXhWV0IyWjF3cUlPODJjL0hERUd2NlBsVGRvVnVWMzFSZ0NGeG5xNFRq?= =?utf-8?B?b2xvK3JaNzhlL29jWnB6WXdVb1llQ01qeWUzMGw1c2xWV0dTVmhRR0hzZ0N1?= =?utf-8?B?by8yMWs2WlJMbm5xZ0FqWVozWGZSM2NtZXJwUUVJU3Vqbmo5SlNia2hkRmw1?= =?utf-8?B?TGkwby9nZDV2S3A1VWtPckZYeDlkdUVKUlhRWThqRVBoMjV6MUVJWGo4M0da?= =?utf-8?B?TUE4VVFYcUZaMGJFNzZCRlArSTFFVjRhbmVFUGN5bVdCSG9aZmdKUkFoRkdI?= =?utf-8?B?S0o5L2czZ1ZGd2NYZUw2bnhwSkVvMVJWR3RtaXBSR3d1TStyQVFPc0VhM25l?= =?utf-8?B?NUp1L2xBOHZRR3Z6YmFSUXZtWkgzdG1UU2hDRFFmTGxlOE5NOWZHL3llYURr?= =?utf-8?B?SGZFUWp3elVBdVN2MUZONGh1YWt0dG1vNlY3N3k0SUhjZEJwYUJLVVFzT0lC?= =?utf-8?B?bEI3aW5iZUFid0FxaUppRmJjUjJoVFVvNGJUQ1FEazQvTUs4dGtqTURwc0ZM?= =?utf-8?B?Q3ZQeDlsY3FhKzhBWGpuNzZ4bzNiTVd4TE1vNUxvWTBDL2ovSEhKNFFSTU5x?= =?utf-8?B?K1I0eXh3YkpSSGpVZHRHUnQ1cFNyZnRJekZYUlZ5ekt6cVhBUTlXRTl1YjZ5?= =?utf-8?B?TDdBRmpYSDB1OTR3MTlqWndkUzVZQXNNcUdBc3J6d2dQOFVsYlByNjQzQ0dw?= =?utf-8?B?bDVvMG1EU0w4NjFRaC9mUFVla3EwTUhvUURVZ2N4RDA1Y2d5L3JrbW4zS3c5?= =?utf-8?B?MkI0dUY4U2FuRnc2VlNtR0JHOWI2Rm1WbUw5QXhnNlo0ZS9aaEdGTkFndXQy?= =?utf-8?B?Q0pVR25rTWp4ZCtrWHhzYmtHdVNhaER1dWFKRFcrVTVSVFBuNWRrMTZPNHNr?= =?utf-8?B?MXJpMDMzUmZ4MHE1QzFMSGVWQlRnUlBKaEh6cjMxS1ByR0c2MENjRkc3MC9L?= =?utf-8?B?UUFJVTdwSVpQYTBQbHcvVjNlelV1eWtVK3BwWW01dEJqS1k5S2lIblZwNk93?= =?utf-8?B?dUEvTXNwRHc3Tkk2QmFHZGxCVU53ZlVoNXBoM05iQmJaMUpPT0c0OWxST010?= =?utf-8?B?YTVueERkUlp1VUU2VG9mcUtlT2Q0Vzg4dUZJVVAwY255OG5vbW1ZSFhHNDBI?= =?utf-8?B?NXQ3UlZkVnhFSjVkSDF4NStCdWIwQXRPb3RHdjhLQ2VRWFdiWmNLR05lSlc4?= =?utf-8?B?ZlUycjMvenlOV2hCbXVpK284WDN2LyszVkdQL2N2RXp2N3lvTXk3b0d6L3Ni?= =?utf-8?B?bmNjRm1NYmhxOVl5RnhLYWczc1hUV3NoaDNJd29wRmhxdXA2aGhTZnJOT3oy?= =?utf-8?B?QkRKaW5XZVNmWlVTRnd1T0FzQy82MDZ1V21YQldGTWNvOHI5KzJaYW1maHhy?= =?utf-8?B?VlhJTEJVeU1icDJFL0VhazFzc3lrSXdad2VoZ3Mxbks4d3lJMDFlZzRQMkpm?= =?utf-8?Q?9Gyx+HWQHBubmye9ynnE8JCoK?= X-MS-Exchange-CrossTenant-Network-Message-Id: c0f0d35f-6036-45d8-84da-08de3846f108 X-MS-Exchange-CrossTenant-AuthSource: DM4PR11MB6020.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Dec 2025 23:50:47.8494 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: nsDCXi2ZlImJtJ1ApqlS03sMVXBNFJsSzaulYLGRSY0LJNrHsDap88qCEf2B59cqXYcRwp8ZpFiDwcyl4Epu6Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR11MB8104 X-OriginatorOrg: intel.com On 12/11/2025 12:16 AM, Peter Zijlstra wrote: > On Wed, Dec 10, 2025 at 11:05:33PM +0900, Chen, Yu C wrote: >> On 12/10/2025 9:52 PM, Peter Zijlstra wrote: >>> On Wed, Dec 03, 2025 at 03:07:28PM -0800, Tim Chen wrote: >>>> During LLC load balancing, tabulate the number of tasks on each runqueue >>>> that prefer the LLC contains the env->dst_cpu in a sched group. >>>> >>>> For example, consider a system with 4 LLC sched groups (LLC0 to LLC3) >>>> balancing towards LLC3. LLC0 has 3 tasks preferring LLC3, LLC1 has >>>> 2, and LLC2 has 1. LLC0, having the most tasks preferring LLC3, is >>>> selected as the busiest source to pick tasks from. >>>> >>>> Within a source LLC, the total number of tasks preferring a destination >>>> LLC is computed by summing counts across all CPUs in that LLC. For >>>> instance, if LLC0 has CPU0 with 2 tasks and CPU1 with 1 task preferring >>>> LLC3, the total for LLC0 is 3. >>>> >>>> These statistics allow the load balancer to choose tasks from source >>>> sched groups that best match their preferred LLCs. >>>> >>>> Signed-off-by: Tim Chen >>>> --- >>>> >>>> Notes: >>>> v1->v2: >>>> Convert nr_pref_llc array in sg_lb_stats to a single >>>> variable as only the dst LLC stat is needed. >>>> (K Prateek Nayak) >>>> >>>> kernel/sched/fair.c | 12 ++++++++++++ >>>> 1 file changed, 12 insertions(+) >>>> >>>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >>>> index b0e87616e377..4d7803f69a74 100644 >>>> --- a/kernel/sched/fair.c >>>> +++ b/kernel/sched/fair.c >>>> @@ -10445,6 +10445,9 @@ struct sg_lb_stats { >>>> unsigned int nr_numa_running; >>>> unsigned int nr_preferred_running; >>>> #endif >>>> +#ifdef CONFIG_SCHED_CACHE >>>> + unsigned int nr_pref_llc; >>>> +#endif >>> >>> At this point I have to note that rq->nr_pref_llc seems like a horrible >>> misnomer, for it being an array, and not an actual number like the >>> naming suggests. >> >> In the v2 it seems that rq->nr_pref_llc is not an array anymore, it > > From two patches ago: > > + unsigned int *nr_pref_llc; > > Its a pointer of some sort. > > Ah I see, I thought it was the variable in the sgs structure. >> indicates >> the number of tasks that want to be migrated to the env->dst_cpu (dst_llc), >> because >> these tasks' preferred LLC are env->dst_cpu(dst_llc). Maybe renaming it to >> rq->nr_pref_dst_llc? > > Like I said in: > > https://lkml.kernel.org/r/20251210125114.GS3707891@noisy.programming.kicks-ass.net > > it might make sense to put it in struct sched_domain instead of struct > rq, since then you can allocate and swap it right along with the rest of > the domain tree. I'll think more about this. Currently the per cpu rq's nr_pref_llc is used to identify the "busiest" runqueue. The busiest runqueue has most threads wanted to be migrated to llc_id(env->dst_cpu), because the threads' preferred LLC is there - in this way, the migration success ratio to the preferred LLC would be higher without breaking the imbalance too much IMHO. So we might have to track the per cpu rq's statistics during enqueue/dequeue. If we put it in the domain, not sure how to track that. Thanks, Chenyu