From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CH4PR04CU002.outbound.protection.outlook.com (mail-northcentralusazon11013059.outbound.protection.outlook.com [40.107.201.59]) (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 B75B021C9EA for ; Mon, 8 Dec 2025 17:35:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.201.59 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765215338; cv=fail; b=iN4TB/VfSmHy3cauRTE5HHcTP7jN2BVazrXB446mJihxgqoqUqs21gjNhhJ+hRdFe/gnN+zRsvjojE/ouMYlTUtTpEdjTRifJO/56RhcDQhbtq+pBpPHx2NNJoYbq0QdL+MQQdSdnv5hPpGTA+VKqYffhIbh5YkZG5/HIK+OoW4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765215338; c=relaxed/simple; bh=x6uecIa1WJbYApKjAGpdZ1uRzTemmg+tC+pmQhx0l/s=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=lJkuJIabeVK6O8t1MaFhEMawgqeNwHMb4bSs33fSmnatG3ZuHesQdWZQWI6Vw9VNLQosEIcmWrh2MfAxEKFkHd/VpKQFjdh1zkIsC4Z20FuNV+cnIOFEscgXG+tvX3fwpyPjF4b0i3lOxdM3nZ2WVz958ilc2eH7qg35AHSa7mE= 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=TDjGTmO5; arc=fail smtp.client-ip=40.107.201.59 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="TDjGTmO5" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=GQdqduo6sbflM6XpglP2ikjKbObQ2kQE6OcnB2r7c6abXzttE/9NY1O/yWvQUOPqmB5gnF+ZT7Nzf9zx22UJSWod8qzEoMufw+tjNeQUqSup4JTkAuLXCFxXCq5fUMEFbkmD0N7fPgqc6uOTdP4Qdg2s/EADTeAdo66sxVVjx0yImi8sZ/4fvCFzKuY34ern77HpMogOPQ23WSNbdhxgB/8X6NU3ep3qj+UltacpRjG0AJXt7xUyMgW/8NAhyBeubn0z9o6yj78m8Yw+SaU/pF5mRfdYL3Mav8s1VFzSiYh8DHzwt335X05u/164Vk/CJrIt4oxym6rdpxz5QDdZgQ== 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=xFsEmEqn7xkaGxDxH0A0KtPUKUvhVQ06isJn9HOSHuA=; b=fTxXg6FEZYxP+RjXi191qWVTwvs2xOa2MRi1W7RP20jjANNgCMjv7xr5Xrdkof62hWHG/OUQkqhdDPpqypXS8n0pyX4EgMTKbXYTXZiHdNtiiv6/xx6r4kT7bopBNsn9/+2WRVEtM9Bc+lvFNNtq2qVf4L7ORZh6XLkQhkPv5/eeRLg9WsiZZhcvsgIWUP2Edi9oGzpW9DRy+gUNWj4scWVSG8EzkPmB/kE9IbarVA30j5TSMByyndZ7bF7HDJfGW5qUa8ae4+NW+TgIkhDOqUefFRSlL+GbzElmA4SUSZ66/yaNciLFO6oTDgz1Yvyn7zjBOdMeE9hYlfZQlbE1VQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=arm.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=xFsEmEqn7xkaGxDxH0A0KtPUKUvhVQ06isJn9HOSHuA=; b=TDjGTmO5cSYctQFLc7bBnQ00mtwxGjHauayrdiw60IHn95ydFhTmPnSc7dnB83eINkiRMV6/QH0UYHedZn7jYLOT9PbFtc5D+MVz2e+SWITyw/CUpSeN/KpDOAQAOn9HGdCTKXlOwtpRUZERjnWwBmCFKWAAP8TZsn2Y632psVE= Received: from CH0PR13CA0051.namprd13.prod.outlook.com (2603:10b6:610:b2::26) by DS2PR12MB9565.namprd12.prod.outlook.com (2603:10b6:8:279::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9388.14; Mon, 8 Dec 2025 17:35:33 +0000 Received: from CH3PEPF00000012.namprd21.prod.outlook.com (2603:10b6:610:b2:cafe::8f) by CH0PR13CA0051.outlook.office365.com (2603:10b6:610:b2::26) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9412.5 via Frontend Transport; Mon, 8 Dec 2025 17:35:36 +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 CH3PEPF00000012.mail.protection.outlook.com (10.167.244.117) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9434.0 via Frontend Transport; Mon, 8 Dec 2025 17:35:32 +0000 Received: from satlexmb08.amd.com (10.181.42.217) 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; Mon, 8 Dec 2025 11:35:30 -0600 Received: from [172.31.184.125] (10.180.168.240) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Mon, 8 Dec 2025 09:35:26 -0800 Message-ID: <6236b897-8924-4065-9193-30f8fd2dfda5@amd.com> Date: Mon, 8 Dec 2025 23:05:25 +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: [RESEND RFC PATCH v2 28/29] [EXPERIMENTAL] sched/fair: Add a local counter to rate limit task push To: Christian Loehle , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Anna-Maria Behnsen , Frederic Weisbecker , Thomas Gleixner CC: , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , "Gautham R. Shenoy" , "Swapnil Sapkal" , Shrikanth Hegde , Chen Yu References: <20251208083602.31898-1-kprateek.nayak@amd.com> <20251208092744.32737-28-kprateek.nayak@amd.com> <861ae06a-5c9a-47ce-a290-709785b28833@arm.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <861ae06a-5c9a-47ce-a290-709785b28833@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PEPF00000012:EE_|DS2PR12MB9565:EE_ X-MS-Office365-Filtering-Correlation-Id: 5d47285f-c0be-4c85-bbf5-08de36803023 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700013|7416014|376014|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?YnFmdUcxUEhrcTFNNFY3ZmhYMnduY3QreFhrRWVNLy9uOEE1QXYvTlVoRnNM?= =?utf-8?B?d0QrL0ltcHhwQ1ZZbWc5aWFYanJkeTQxV1dGaUlzaForSVA3SjB3ckN5UGM5?= =?utf-8?B?MzVPQ0JNTElMYjJ1RlB6WGNKMjU3WkdNSEJXUGtMdjJ3elVoT2NmNG1YK0tT?= =?utf-8?B?WE5VRjd2cnNKT2JwclFORERZeEdFSmIvTEx2TUd5Rm5hTHVmeE9OT2ZFT1hj?= =?utf-8?B?c2YrVk0rMStWWkkwb3pSWUR4OXoxTitrN1hCNWdjYmNSbXRabzRLbHIrekpx?= =?utf-8?B?WXIxN1VYek9CRC9abTRic0g2TlVWd0J6eGVpWndEVlZiN210OVVXcTZNUERU?= =?utf-8?B?YUxOTTRtM0xXT2E5bW1sM3YyUzBHM3dlYWlVV1lWRkRvbGRmQlpOR0QyMVNt?= =?utf-8?B?T0V4STBiRFp1ZTBzU3pOUkcvTUNPNzJQdnJmenl0MStNWWJ2UVdQTVllMDZV?= =?utf-8?B?Ym5KTXhIYmxJTU05K28zM0UzRWpnelp5OG5oM3QzY2NLNTZMRXBybnZ0eXR5?= =?utf-8?B?RDZ3aDVJS0czUzlSd0ZpYmdMbHNjKzcxUld4NlIzc2R2alFaUlhPNWVRYnMx?= =?utf-8?B?ejVCSWJ4aUdaUEV3VWxxZm9MRVRMb2NVcmltYXZLMXBYTkFud1p3ZlJMTExU?= =?utf-8?B?NzBQMHRwczhmMzRER3U4SVBwdml5NEZZaDlPY0ROQ28veWV5ZTYraVVWek1O?= =?utf-8?B?ZjczNXlZa1JqYVhZVFowcGF0SGlWc3RPYXNFWENXMXd1azlyZ2NwS2hCQ2Vz?= =?utf-8?B?Ujd3cmdXck8wZTJoVzJUN3NDQ1VESkRXeWJaNUVIdjdwM3l5cm9xOFZoQUx2?= =?utf-8?B?aEJ1bUdJQXUzWkFGTkEwbTBhd21IcDA0WUJjSUlrQnRPemFFUHJGOUZURkxO?= =?utf-8?B?Z2FoTVlIZFdrT25DSUJzK1NwS0JCLzhuZ2MzV3M2Y1NrbUY2QnhQVXZWTlA0?= =?utf-8?B?Rm1RT1lmSHZybmFyWlZrTWVFSG9JalREZFo4UHJydk9yemI1N1oyNHZtL1gr?= =?utf-8?B?MFh0TWE5ZTJNZkltMmJ0Ny83UUVhMk1UMEpBZFZvNDRuWkh3RDc0WnRxU2px?= =?utf-8?B?amhhWUtlMUordnY3UFl2aDBJVkk1WlhIMGZuVWY2L3hHSE9qRlRDZTdTMkNZ?= =?utf-8?B?TEhjTHJVK1dtS0VwVlIyS3AxRnhmYXNEVjZDOEl1Z3JtMC9RS3FVTUQrL1hC?= =?utf-8?B?aEUwUHFBNlI2YnIzK1dVckYxQkg5VmE2TWxCSHY3WkJOVERKZGRVNCtoTWps?= =?utf-8?B?ZzlYY3Q0d1UwSVlHemFmaStJME0reTViM1BIVWkrU2FVZmpzd2t6UTYxSUF0?= =?utf-8?B?bUZUUEU1RlJnbFRORFB5SEZ1TEVTcUVvNVJxTVlTNUV6Um9LRUpYWWdBZVZI?= =?utf-8?B?VUliRnNpWUhxQmJ1VXo5cDZwK0RBNDREWlE1cFBmKzBiaVJQZmdKK09LR1Zv?= =?utf-8?B?RkNJMzhFaDhtYzJpWCt1WlN0bWxpZVhXS1FBNnBNQmRUZWR4eVNkekYvQThU?= =?utf-8?B?ajRyZXN5UFBhazRmWkpXb2ZFV3lXMEFBMmJFWWxjN0VURnNxN3VOczdPMGFJ?= =?utf-8?B?S1plNktjWkUxemVEa0Yrd2MrM3NtMVVlQ21TY0ovaTFTdXJtY0M3ZXFkTURN?= =?utf-8?B?bXRDeHREY05sQlNVR08wQlJwdEFnbEIxWXRaMlhsRGVRRDhBaVJGOGtOVWZW?= =?utf-8?B?SWhPdFMyVXp1c2tyY2lOZjV6bDRUNmdUUktZY2VZcUlkbmRwOXRqMGFGQ2Nm?= =?utf-8?B?YzdDdHBCRmFKaFk4VzF1TElMQXdZL1V4Q0xjRC9GQ3VRZHFMMWliSncxOVBD?= =?utf-8?B?MHlxYWFMaSs1TkZmMVBQemFDSlhxZ3dUTVU2MmswSjhxL3EzaXlhNVlqVkxZ?= =?utf-8?B?SWNER0FROTZGbmVIQ3FoUmVXakVNYzVVWVpUaEpEdUFJaVVUZXhnTUl0OGZ2?= =?utf-8?B?TnIyTHUwbXNQd1c3S0hzcFYzNlhSMmdZblMweCtxNUN3WW9zRHRVdWsvak1l?= =?utf-8?B?bkhCcUUvTjdkZFRBckQxaExJSSsrUXNkblN4VTBvN3dKUjBhbU1RRURxS245?= =?utf-8?B?VnNJNUNkcENESGpCNHFnZGRYdWg3ZGZmYUQ4ZFdKaDB4a2tPQlNKTWZub3F4?= =?utf-8?Q?wwDY=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb08.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(36860700013)(7416014)(376014)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Dec 2025 17:35:32.3962 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 5d47285f-c0be-4c85-bbf5-08de36803023 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: CH3PEPF00000012.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS2PR12MB9565 Hello Chris, On 12/8/2025 6:03 PM, Christian Loehle wrote: > Just to confirm, but this patch is included when the cover letter mentions "push" for the > benchmarks? Yes, this patch is included. > Did this help the regressions then? So without this, I was just using tbench as a smoke test - server client pair sending a very small amount of data and can lead to very short sleep time. Up till 64 client there were slight improvements from not rate limiting but once I hit the fully loaded case, tbench regresses by up to 10% mostly because of lack of idle targets but also the CPU doesn't hit the overutilized threshold to cancel push attempts. CPUs are still considered "nohz" until the first tick hits and at a high frequency of CPUs going in and out of idle, "sd->shared->nr_idle_cpus" turned unreliable in my case as a bailout threshold, With this rate limiting, things are within 2-3% of the baseline. -- Thanks and Regards, Prateek