From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DM5PR21CU001.outbound.protection.outlook.com (mail-centralusazon11011070.outbound.protection.outlook.com [52.101.62.70]) (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 3BEB84C85 for ; Wed, 24 Sep 2025 04:21:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.62.70 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758687703; cv=fail; b=IDlqb98NSUQiI0a/4LSau2kShVOIA+Ew/2qiy5hBevbb3rwJP2Y98/V4HVH35xWsdXD8Om0sfb5e6dneizHZgwxm903zXYvg2nhJ9vq3+sebKdJxjA2BfCqs2WUvl80CpndMpcdPFr84FOpHXiXwSrgLe/HbmmTiFzCv9d9MrmA= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758687703; c=relaxed/simple; bh=GwF6YfRAj0H8l5RBRjt988Q7HGj3qyuqwQ76pz1FtHQ=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=YrcWYgXJyrieaHjMOHsI337aOcigsSGfeJdTwFZY0BeSTF/ccRYXVq5ar+4F8znNkMg3jDsHGeEKWdc0alaNenLEdoOnI1eGHvjsKjxHEKlBMmRgRrBwIhb8Eryk99nDgEJG7+jdRQ6H8jMFqFioNszMTv8YkmNa5UJ4Zb0IP5c= 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=m0vDuDMF; arc=fail smtp.client-ip=52.101.62.70 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="m0vDuDMF" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=X4vCRZZOe3WYweeYTj31BpnXvH8fm6iMkfQZvKEnZ9HnQSoR+xKxxsm0rjjeyhkWQeQQ59qCOixud09kLVA7rmNKm6FBX8t85MpfxITG4vI8Th8NDTfOkdcbibTLR0nxICNSFqjf0ElUN+yjS6oIfg+lSly2NrAtJMWmoaRgRV3glSydSplOH20qLAOs2RPMUTBBYHrBUS+C+r5BOQi7vc/uotnkrjuA95PaLcv5HV2LNkevwRsrh1LWnDABclo6LWDut4Eqt0c7ThM0AocGNgrt1w2aIqTRQUsAgdoqdjKMWQbZoP6fHHoyBOcWQlp9YHMohpEIx+F8pX8GhJf7eg== 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=d/IhMfN98hh/mDRA6wug1wbKKJeKppL7WZkp11+8nEI=; b=aJTBo7S6fac9cofIH2GiLxZp2o1ikElvZA9Pprj9KwJW0b52r3N4nJPSwsVrXeaxY72v0OnTHodC+ffYlpGfnHy8yJpAwG7qzwFkNPTBuafs4u0Es06dwBEdCwM+TLPSSOkq7YZhaOKyCa0EEjU4/E2i6bLVWv8n4r7N6dmDZVmsgkqtSAGVwDZS67frK/JUKpjck5iKkb0EKdstIrZhQ0AzF5SS7tuHeQUmB8iYZeBRkAJm47xZoEkra8COkzHtpAjX5IQZf41xvmDcGGPiSGcWwletA8zv5Ekpvo56Rg6O9ZDQL7vKY4UFHZ1XS0UdxF2ZlEiQMNaQRrjR32Rutw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=amazon.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=d/IhMfN98hh/mDRA6wug1wbKKJeKppL7WZkp11+8nEI=; b=m0vDuDMFZHXhtGNjBKF/Cyb6/aKFP32g+DLHdihjy5FUjnXWooABLj0xSJMoopHsdva1ccSze0n8kjlitz7ChFaNIQci3bxKf0wa7NbE2Rt+ZlL+Tm9ik5iWqtBg9ezK6jV9lJ87HSkHnJg86/OxDShciAknTUFHSbFlEReZXL0= Received: from DM6PR10CA0007.namprd10.prod.outlook.com (2603:10b6:5:60::20) by IA4PR12MB9762.namprd12.prod.outlook.com (2603:10b6:208:5d3::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.19; Wed, 24 Sep 2025 04:21:39 +0000 Received: from DS1PEPF0001709D.namprd05.prod.outlook.com (2603:10b6:5:60:cafe::fa) by DM6PR10CA0007.outlook.office365.com (2603:10b6:5:60::20) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9137.20 via Frontend Transport; Wed, 24 Sep 2025 04:21:39 +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=satlexmb08.amd.com; pr=C Received: from satlexmb08.amd.com (165.204.84.17) by DS1PEPF0001709D.mail.protection.outlook.com (10.167.18.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.9 via Frontend Transport; Wed, 24 Sep 2025 04:21:39 +0000 Received: from satlexmb10.amd.com (10.181.42.219) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Tue, 23 Sep 2025 21:21:35 -0700 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, 23 Sep 2025 21:21:35 -0700 Received: from [172.31.184.125] (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, 23 Sep 2025 21:21:31 -0700 Message-ID: Date: Wed, 24 Sep 2025 09:51:30 +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 4/4] sched/fair: Add more core cookie check in wake up fast path To: Fernand Sieber CC: , , , , , , , , , , , , , References: <20250923093001.1218488-1-sieberf@amazon.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250923093001.1218488-1-sieberf@amazon.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS1PEPF0001709D:EE_|IA4PR12MB9762:EE_ X-MS-Office365-Filtering-Correlation-Id: f9efa2c3-43b8-400e-858b-08ddfb21dbcf X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|82310400026|36860700013; X-Microsoft-Antispam-Message-Info: =?utf-8?B?cy9tblNiVHlpdUhRL0dVdnFhR1lKQjNtSzJvd2NaOEJjTXhIR2d2Qk45R2Uz?= =?utf-8?B?U0JCeUhCbm96MVdXTDlSOXhEVkFTYXBXZjV4ZGs4V3p5MkY5UkVlM043bWdH?= =?utf-8?B?ZHd3ai9hUTBCSGgrWVJDcXcrQ0pzOTZjd1NKOXFzeENOUndnZWFTZjhxYm9h?= =?utf-8?B?M2w5UnZrQkVvTWJHS29PTGNBSjc4OWk0TXI1dlFibks1dVhhZi9IRzJRUG4w?= =?utf-8?B?OGg1R29QNVlEc3YzemtRNDZrbDRQbGxRWWk1cmtrT0k3OHVDTjJJS0p1bldS?= =?utf-8?B?TDEwNDJlaDhDL3psWmh4MTZ6UnZjMjVLNXRzdmJnb2wxajJBek9vQVBUYmJZ?= =?utf-8?B?Y1BSOENhQTVFUDR0MUNOOUMyUDB6MGttYms1dFpTdktOVlRUV1B5NjBNRDJ6?= =?utf-8?B?WGVibFc5RTcrWnpSK2J3VmxOWHIzSDR2S2krcFE1cHoxUldzRUUrUjJJWkZF?= =?utf-8?B?MnhWZUNXZ1FjWld0ekRVRWY5Z3c3YTNaQmtCWXlsL3ZTaStVOXJGaXhpR1Jt?= =?utf-8?B?NjRURitOeC9LNnQyVEZnVG5weXBVdzBBRTFlZG4xbWZuU3U2OFBrY0YzU0xu?= =?utf-8?B?aHNxV09KbVpxUk9jZGdldTNpcXltcktmVHVGa3NNalJlcEZBYUJWR1F6MUU4?= =?utf-8?B?eC9CMTBXQVFXSU5ic1ExYzlaZzRnZ0JtVFc1U2lsZEpxZDBVdEdCcmp2NTFU?= =?utf-8?B?L2FtY2dqMnZMTTcvd3lJUEd3REIzUGdoSlllb1JmZnpQWGJKVis1b1BRc2lt?= =?utf-8?B?RlpWL2JjcndhR3ViNkRId1QrYWpKcGQxdjZUUDdmd0h4aExkTXhKMlJxdFRO?= =?utf-8?B?a1l2SDZ5Tko4YmF4VHoyTE1jTDRlKys1aDlLb0hZQVM1TmRTaXdzYUYrbWlK?= =?utf-8?B?SnlDUVdWSUkxZUhnU29hRjYwSk5DZ2x4MEJDQjJYdWlpN2VzTkM4cHhXcjFQ?= =?utf-8?B?ZnVnYUhMR3B1WUZSb3RKRFVZYjArdzAzTmt2c2QyTTljdzF4akYzMytzVDV1?= =?utf-8?B?eHplREtidm9oV29OWVhveDdzQnY3Zjg0TE5vWVNqd25ZOE94dXFoYllRWUxj?= =?utf-8?B?TnBCNHdvaUhYRHhKQnAvZkRZSi9CeGdKUkNSWDdmd0I1TmtSSDdhSmdUZW9P?= =?utf-8?B?a1FRVkN6YzdnL1NCNzd2VUNCcVRMYWJzZjRTVkRzMzhTSi8yRHYyckg1empa?= =?utf-8?B?QW1uZ210YlhBSWRWdXFVUWRwNFlaVldUQTZmVDNlRVZESW5iOXhMQ3RkbUVl?= =?utf-8?B?ZGJwbUlsRmRYSHg2NnlPZWxKYWVhSHlzb3kxc2dxSm53ZGJSVHA0NEpwU29X?= =?utf-8?B?dUhBYVpjN2cvN3hJVDhzQlpJQzhCZytrMkFya1l1OGUyV0xTRThQMFllWFMz?= =?utf-8?B?ZUdkK3pUME1VeCtqSTUrdFVMck15V2xEa0hnNDd5Yk96Y0FvQzE2TUxSNktj?= =?utf-8?B?Zk1ycDRYQ3UrSERiU24xOEs3anhNYUkwREdnQXlVbXoxNEdCSjEwQjNEVDZC?= =?utf-8?B?YWJJNW95RG1lWWJWUnd4MFdQaTgyUzFadnV0dDUrY2hoR09mZzZCSE90QTc0?= =?utf-8?B?RlFQb0o3dDloZE9aRVVOcC9JaDNsSnBES01WVGhvWFBLZDZ3YkprelMvSmpH?= =?utf-8?B?d3FpeFlaeUM2Qm1iS3d4aUNRRE9IbXNjSnNVRW1VK1VIZk9Ga2VWV2hUVFF0?= =?utf-8?B?eWU5Und4RkFlQm1NUnFqaWM1cGtPTGw4eXlaY1lyQ0w1bnNyNzVSYkt4dFlw?= =?utf-8?B?RU1XZFJTeUpRWE9BMmp0Mlp1N0Izc1hjbUd5cXRBbWhHM2l0M1I4UVFid0hi?= =?utf-8?B?VEZmOW8wU2JTOWI3ODdwekUrcW9lOGRjYTBUSFpkdE9YTnRIOG1sVTlRTWtX?= =?utf-8?B?WHRiSENIR2NzcEZVLzhxYjFJUDc3MDRqeXB2U3ZOMG40bXczVm4xY2l0eVZB?= =?utf-8?B?TDhoOE1JdkRKZDlNdi9LRXZJc0F2WllFVTlNY3RnaTQvRDhKRlY0NmI5cWJR?= =?utf-8?B?MkFQK1JqVXJnY2djOFhIR0R4UXByR1ZZbWRsZklTWXlyY3YyUzdHZ0RQcmVr?= =?utf-8?Q?BQY2k/?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:satlexmb08.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(82310400026)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Sep 2025 04:21:39.5935 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: f9efa2c3-43b8-400e-858b-08ddfb21dbcf 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=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: DS1PEPF0001709D.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA4PR12MB9762 Hello Fernand, On 9/23/2025 3:00 PM, Fernand Sieber wrote: > Hi Prateek, > > On 9/23/2025 2:25 PM, K Prateek Nayak wrote: >> So with Patch 1, you already check for cookie matching while entering >> select_idle_smt() and now, each pass of the loop again does a >> sched_core_cookie_match() which internally loops through the smt mask >> again! Seems wasteful. > > Right. The change in select_idle_smt() is unnecessary. > >> On an SMT-8 system, all the looping over smt mask per wakeup will add >> up. Is that not a concern? A single task with core cookie enabled will >> add massive overhead for all wakeup in the system. > > In such a scenario there should generally be no looping because I introduced an > early return in patch 3 in __sched_core_cookie_match(). Perhaps it's worth > extracting this early return as standalone optimization patch? Something like > this: Yes, that would be great! Thank you. And also please include some benchmark numbers either in improved core utilization or the benchmark results actually improving from these changes. It would be great to know how much things improve by :) -- Thanks and Regards, Prateek