From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CY7PR03CU001.outbound.protection.outlook.com (mail-westcentralusazon11010068.outbound.protection.outlook.com [40.93.198.68]) (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 964B124B28 for ; Wed, 8 Apr 2026 03:07:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.198.68 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775617629; cv=fail; b=OCpoexcSgeN0CI1yBhtsv7AwERBAwdLIQ6KNuHoa/MUl+mfGQaKJnpF5hWtoUe6RIKNwHdIjmXjRoOSb9+OXKerpy95JrHHAp1oL9yRp8TfBfl6yKDO8kewQuMaPQgYvECq7s+7fIzPxFhUYEDFVCl5TboRdXTwMVtM15nM1kek= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775617629; c=relaxed/simple; bh=1/YN7ATtBWLqjdzusuckFo8QuAK9Wy7CuLN4+VFC0i0=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=iEDYxgZ5/UxYHAz3aJ5HqmKeBPjLZ9VX6oY9bmMgs5bFZpyY2BomkNg0tvxW81bJMLnvRVd6LyE1t0kEPIZlIf8ZD/bweagVR/qOJ9XUyYWkRnBkWdNNOu0xrYBTEx5dDqsAX/YatKoY9MbeBBaz+ILNTt3cBcYjVGD1EfK6MUE= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=kdXnk77+; arc=fail smtp.client-ip=40.93.198.68 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="kdXnk77+" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=yfZINV82NHwbzD4+d6muHf79GsU90NVzFwZqxAnCEJs1OcVIbWf9kKYBTfBnj/uTZca2DV1ABKZAGZXOthC9h0Fm/kZxuEmUuFgNaeVx/E17jfPgMRCG+/w0/04UV5vWWAsFLLxX8cXU9aTnuYb4+wb/kBtSWl9bOdulkzUtC/UE+h1K7JffdIAHBlIVpvy2eISUNzVvYVg2/AKrr7qmK0hUZeSLD2P9jb+inbnpiZ9MUkn7DM+j0y3irfGC0bEm+LBNP/OSuE/681GdrxnkReHjl7XLBeR0YgjsODN9bEEH9pGcww9kKwR4+UGpWGt50GmRDKQSRlSKRZEIvt8EAA== 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=3QgWPF3u0laicLtjGPgGL4hi80eDeNd9gYRxeU68s6o=; b=J9jnpX6qN9GVd1mvEW1u1Y4PTJmUx7m//n0NwFUWGaytsp/d8Qy5HYpXAgN3teUsY2SeKl+1Ma/WQyYLVHe+kkqHcI1hDavjYd7Vj/QuRhFq3ksgX4MaKWzER0Q51znJFgx0KixeREwhbrpl3Uybif70Hj9NPggn5Gc6UeLhraaj6kAgmA5fxt3mn3bZFbVdoSqlBK92P2yP7d09aUdq5CzEkUMjmNZKm8RDYmGxn16/ddI/OH8lXFetXZE9bvcRXDiX9RKD3Nx9JKZnuzXfCnFD091+FzeM7WomvXzBwoW/AVoyiJckk2kDFkQxsT8LZb/OR/58d72ZOQk4wjIwug== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=linux.intel.com smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=3QgWPF3u0laicLtjGPgGL4hi80eDeNd9gYRxeU68s6o=; b=kdXnk77+OB+UW4z6po0IJ8CvQ4sqSnqE6Co7VIQDxnDaZcWDq1H8T9mrijz0+uV9IosbAqRrq5S7i1TcgOS1tSn4KCWDXPeSqaR1uHZtHaba6/8X9JXOMqIVJf5dtilvn+m43e3/maep3Hs2pv9eeRMeyxbV0B8jzbJ6sAwNdaQ= Received: from SJ0PR05CA0121.namprd05.prod.outlook.com (2603:10b6:a03:33d::6) by IA0PR12MB7722.namprd12.prod.outlook.com (2603:10b6:208:432::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.20; Wed, 8 Apr 2026 03:07:04 +0000 Received: from MWH0EPF000A6733.namprd04.prod.outlook.com (2603:10b6:a03:33d:cafe::3d) by SJ0PR05CA0121.outlook.office365.com (2603:10b6:a03:33d::6) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9769.37 via Frontend Transport; Wed, 8 Apr 2026 03:07:04 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by MWH0EPF000A6733.mail.protection.outlook.com (10.167.249.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.17 via Frontend Transport; Wed, 8 Apr 2026 03:07:03 +0000 Received: from SATLEXMB03.amd.com (10.181.40.144) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.17; Tue, 7 Apr 2026 22:07:02 -0500 Received: from satlexmb07.amd.com (10.181.42.216) by SATLEXMB03.amd.com (10.181.40.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Tue, 7 Apr 2026 22:07:02 -0500 Received: from [10.136.36.199] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Tue, 7 Apr 2026 22:07:00 -0500 Message-ID: <2881a07f-ff14-4faa-9da7-3fbe206a463d@amd.com> Date: Wed, 8 Apr 2026 08:36:59 +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 v2 4/4] sched/rt: Split cpupri_vec->cpumask to per NUMA node to reduce contention To: Tim Chen , "Chen, Yu C" , Peter Zijlstra CC: Pan Deng , , , References: <20260320124003.GU3738786@noisy.programming.kicks-ass.net> <63a095f02428700a7ff2623b8ea81e524a406834.camel@linux.intel.com> <20260324120008.GB3738010@noisy.programming.kicks-ass.net> <138c3f9d-309f-41e6-aa72-a3f6bd713bf0@intel.com> <22072ef8-5aec-49ac-9cc4-8a80bec14261@amd.com> <64649c85-29ab-4f70-a0c4-3c83cbdae2fc@intel.com> <20260402105530.GA3738786@noisy.programming.kicks-ass.net> <93d7eb33-c3a5-4498-bc26-57806b73d9e0@amd.com> <3b66e8e8-07e0-4f3e-a3ba-d97133af5162@intel.com> <1c742a1d8ecd8e314d704d46a44e2b8893479e50.camel@linux.intel.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <1c742a1d8ecd8e314d704d46a44e2b8893479e50.camel@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Received-SPF: None (SATLEXMB03.amd.com: kprateek.nayak@amd.com does not designate permitted sender hosts) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000A6733:EE_|IA0PR12MB7722:EE_ X-MS-Office365-Filtering-Correlation-Id: fcb360ca-1f3d-47ad-1aeb-08de951be8ea X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|82310400026|36860700016|22082099003|18002099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(1800799024)(376014)(82310400026)(36860700016)(22082099003)(18002099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: qdDZQNanICv9FVRu9liCiQQ/v+DT73Dp9cfeqERLV93v8VJUA2KL3DefGshix3f4oy10vV6bSreOK828UlTF0M3BXW0WnvSsb8kcMk3E9LzD/BqulNeuvMrLRt1aSxMjK4xlAsKSP0MB20h+j3DvddAdf4dRq+dH3YNwxY/wg7r/uyWGoAfMw6nAVKOtZ7MWhRdc5R6ZNrWn3G5Ze/AxBUObakzli6hAb6wxcnlJIJpmeTYxqQm41Tqf60CgyFAzvHMl6zHYhkNS6vSJ5vztzyupVE0hxJ9XSThRIJNtIwax+dDFuO8VJ0yoZ+/g+8nt+yt40mQnJmDZMwieNvQrcjIDiKTF+oi5h8F8SlR5/1gPvaWeKi779AM4NeQfTDRewKgMjpohctfyRGOOmkzZnNqa8e41ZUHffxSI2XvawkB4Kd6v7e8kv+eNwVy8Trox X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Apr 2026 03:07:03.6161 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: fcb360ca-1f3d-47ad-1aeb-08de951be8ea 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: MWH0EPF000A6733.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR12MB7722 Hello Tim, On 4/8/2026 2:05 AM, Tim Chen wrote: >> And regarding your other question about the calculation of arch_sbm_shift, >> I'm trying to understand why there is a subtraction of 1, should it be: >> - arch_sbm_shift = x86_topo_system.dom_shifts[TOPO_DIE_DOMAIN] - 1; >> + arch_sbm_shift = x86_topo_system.dom_shifts[TOPO_DIE_DOMAIN - 1]; > > Perhaps something like > > arch_sbm_shift = min(sizeof(unsigned long), > topology_get_domain_shift(TOPO_TILE_DOMAIN)); > > to take care of both AMD system and the 64 bit leaf bitmask limit? Ack! But do we want to separate CPUs on same LLC domain across different cachelines in 64 CPU chunks or should we use the rest of the padding to represent them? I'm collecting some performance numbers to see if makes any difference under high contention but have you seen benefits of sharding the mask further when there are hundreds of CPU on the same LLC? -- Thanks and Regards, Prateek