From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from MW6PR02CU001.outbound.protection.outlook.com (mail-westus2azon11012000.outbound.protection.outlook.com [52.101.48.0]) (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 27F34385509 for ; Mon, 9 Feb 2026 16:53:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.48.0 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770655981; cv=fail; b=J7Xul2ombPfaBCqkBnR94cPBVNVnr3dtZphvcYTqKi7I8ur2PYxIG36NaxdKebgsjH5yECOBiY1sF/RSnbd1xPs7g/J5yPK7LBtAl2TGZeac1v+jOd1ywdIeMGytK8Z3MR5nvOxBjD2gj+qOY6XFIzpqF/tjYt1B/9rgsH1JFFQ= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770655981; c=relaxed/simple; bh=8CtY7/5KLKIbrgk/HX0t+zEhSQU14hOdJ6lGIfs9Q0c=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=R1AFpH712b0ZBHj2af7X3DnBMoFQgOvdAFsIiWkLq7Nf/ry8LxjQoX5tpMlF7lhMllAxMgYrF14qgTSVJCq1+hc3lswT6JXJl1YhXu6TLlPXClo0Jx6l27gY3o9nSiOSNoFFif22WHBPw+zTetax4zfdIm957EB68YiwGb6Fzr4= 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=VDgRM4g8; arc=fail smtp.client-ip=52.101.48.0 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="VDgRM4g8" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=C479SLW5DIV9EeEByIiektNvG/u8XwU+3/XD2LkVPPWX91U31E46RWUL3+jnVvX1AzSgyL8cWInHHDPqHcsClO23P3f4/TW4OFpl3VjBVP+Q6lcxOac9Oi78oEZW3vA0+iBFhS+eFNYMkJkVjXusneP6mlB0u4RwyFFHkZe5YYgYTIVXaT3wVNDnP/biYKt1voE3inLifhQXTxEm+e1eAOTUY1edTK+4xiUUN41nVPpn6emTMNaNKFh6iGTlACYxScBYX0pYZBkNsvhwS73fSO+b44rvadu5kB8N8PIPR+BeGftvT/SlUttd5Y1szOr33d7GRJqQoYqiD3QR2sibwQ== 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=UpNZ8NMZEYwWshs7hBvCSOId8CE+pC64yXvzYsR2vIU=; b=Jsu8pDFZhMzI9jD/LqsYycL9elCUk67gXq2bdBRzKaPbycVbTcxYL2MB/e+iuEep3ndz35DL8yz9debWABDnQLvANGH05P/MvPJrYO4pNLPZFqpCrSX58kEJ1KJzE1+Pqx6yTt55Jp5St1YbrZC2aB1G9nYEcPamqWzf8KR/rO4zhNn3yAm1l6WVxLAT1MlWUVbkpe2u+sJH+i/Z29lrKD6OmP1SzSK0+qomD9H42BxZuw7r20KTNPRiEgFR5VODsqg4YpG3hwq3zWd9R25Pi+GREcszw3i9PY0F4VXbFOrU6AM1W8ZfPGAlHU+HU72alE9/ZC80Xh8HgX0KrsHdEA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=infradead.org 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=UpNZ8NMZEYwWshs7hBvCSOId8CE+pC64yXvzYsR2vIU=; b=VDgRM4g8gM2+sXAcYMC88ZyUBpCgdfFjMIjdGLpxBIFnlHbj5wMd0uB9qQA5NKTWwbWT7IPJygMF7fWQk7Uv5+BiaY0fOw1SUPy55dq/ohis26OypzV38GuOtgJGjOHi/Vu7/O+7AcuQfstcwGX9RIpzkrsYLrzf8fEFakIbd+E= Received: from PH7P221CA0018.NAMP221.PROD.OUTLOOK.COM (2603:10b6:510:32a::17) by DM4PR12MB6038.namprd12.prod.outlook.com (2603:10b6:8:ab::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9587.19; Mon, 9 Feb 2026 16:52:57 +0000 Received: from MW1PEPF0001615C.namprd21.prod.outlook.com (2603:10b6:510:32a:cafe::4b) by PH7P221CA0018.outlook.office365.com (2603:10b6:510:32a::17) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9587.19 via Frontend Transport; Mon, 9 Feb 2026 16:52:56 +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 MW1PEPF0001615C.mail.protection.outlook.com (10.167.249.87) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9587.0 via Frontend Transport; Mon, 9 Feb 2026 16:52:56 +0000 Received: from satlexmb08.amd.com (10.181.42.217) 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 15.2.2562.17; Mon, 9 Feb 2026 10:52:55 -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, 9 Feb 2026 10:52:51 -0600 Message-ID: Date: Mon, 9 Feb 2026 22:22:50 +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 0/4] sched: Various reweight_entity() fixes To: Peter Zijlstra CC: , , , , , , , , , , , , References: <20260130093439.803225718@infradead.org> <4c48fe59-8ff3-41fb-83cb-869409f6fbc6@amd.com> <20260203111134.GL1282955@noisy.programming.kicks-ass.net> <38ef3462-4c4e-4f40-8d63-84dd71cbd043@amd.com> <20260209154718.GW1282955@noisy.programming.kicks-ass.net> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260209154718.GW1282955@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MW1PEPF0001615C:EE_|DM4PR12MB6038:EE_ X-MS-Office365-Filtering-Correlation-Id: 1bb1ca9a-b318-413e-58aa-08de67fbacaf X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|82310400026|1800799024|376014|7416014|30052699003; X-Microsoft-Antispam-Message-Info: =?utf-8?B?c2NJTngyWEVUQWtDYUVkZW54ZExwcFBqc0ZZYkJwbFBNQTJmUmllOHBUczFo?= =?utf-8?B?azZYWDB5NERvbkRqUHRMWGFKaEhKQW9JVUMyMy93VUJ4UDBKdlhUZGtxNW5s?= =?utf-8?B?WVNLYW9jM0hEYzNKdWZVY0JwMWpIdGdQbFd3cm5rajJnOGdBaGZkYmlaUWhF?= =?utf-8?B?dG1lTXNFWmg2TFJaT2hUQzNIWlRDZGNoZ2tNNzJBV2RUd1JYZGNacmJaWmdi?= =?utf-8?B?ZnNKeXB6bFh5aWpCUGVjNEFHMXFMRXA1bW1URDN1RFBMWGJEV0ZuUnpMVWdF?= =?utf-8?B?ODVKV0NxVFQ5RXp0aExNOWFuczBPZS8zblVXaWhmd0lDbGpmUnB5TE85c3kr?= =?utf-8?B?L3BXNXFKcTJXMHZVVVIrUXJpQjk5eFEwMUdMeE9ic0poUWh4QXRZTmQzbzR6?= =?utf-8?B?aG52UDVWK1NCUktpRUM5b2FEQi9rL3Mva0dIYjFIQ2Y1cnRtL1d1c2pKeUZM?= =?utf-8?B?ZzlDMUxJcGdyTm5UUVhiMXk3UzF5M3pseVFaTk1xaTJWZ2MxN3kxcGZ3dDd0?= =?utf-8?B?Rlh2MU5sZzM3bjZpU3NGRWx0L0R3SW5Gb29rb1IvQXVwdXNhUmdOYlFlL0Ni?= =?utf-8?B?OXk5RzlKc0lOV0VUaW5paTl4RE9ZaTkwZGhSaWl0ZDdXVVJTeXJNODFEU2E0?= =?utf-8?B?a0RGZTY2T0lITmp6QVdvOCtpSkdxUjZVeFl5TWpxcEw2NHJNZ1BPb3ZlQzZB?= =?utf-8?B?YlJ1bVJhVWZuVm44YkI5V0JuU1dUR053dE9nT28zS2VKMFMwWXo3N2Evb0ZT?= =?utf-8?B?M3M1T01hSzFwUlE3NVJqSjlVVk03R0ZwYTR5ck9qdkpwK2tlU2U2WGY5WWFj?= =?utf-8?B?MUtSQUNCTzFyTkxLRlZtWFp6a0FtRnNwUGw2dlF1d0dZTFQveUxYMHZQdFpC?= =?utf-8?B?b1gzbzZQZ1pWM1kvT3FZODVXVmx0VGc1RnlEdGZVTHBVbTVJTmZiZFBBNG95?= =?utf-8?B?YSt3K1lwbzllK0NKL29nczgzYjZkYXQrRzl1YmUwMzhMV1hvY2xWMVVHSVUv?= =?utf-8?B?eTBqNEZFb3ZCa1JWdWlyQnBGdE9GdEV4RzN3NXhKN2FMcUluY3ZmRU5LbUNy?= =?utf-8?B?OEs0MmhuU3RyTW4xY29iTjZUeE96b2l2R0RWWUtsZGJUUHNhdUkzeHB6d0l2?= =?utf-8?B?dUxwbmg0QzRkQldnV3J0b083TEhta2ZvcXJROGYvcU9XQVU5MmhVLzREVklJ?= =?utf-8?B?UU1KZm50TWlvNENDb2hXU3hVL0lRUjNhU0VEaGIwNWxab09CdnhHUGZOalVQ?= =?utf-8?B?OU9wdTZUTE9yOUNLSlZzRzVpcXVhWTlhQjVPdnZxZkZHaGIzOFMvYmRjNEU1?= =?utf-8?B?Q3dUUWtvRnBvWDhYOVlQcUhXdUpUWXMyL0s5aFhSVTRhYm4zSG5DNWYvMnFj?= =?utf-8?B?Vy92OFZxTXBtd1hUV3RvZU1ueEwwQ0dMbEIrWEZTNWsvQ1VHdWpQU1NkbUNU?= =?utf-8?B?djY5ZG1EV0ZicVRIY0lSV2sxODFLVmdCd1RDVE5nemNzZkV0YnhEOFRUT1A1?= =?utf-8?B?RFRzRjlPQml4RWhPUVB6b2Zoa1Q1aUtNYUJ2UzNYTitCM2MrSFFOWXNlRHlm?= =?utf-8?B?RkdrZ09zQUU0UTVxQXpoQ0pJZlJpWWhreENOTlhDOGhtTWFqWFFTR1dKR2Vk?= =?utf-8?B?Smw4dGU1YUgrVVl4eVlWVHBkUjlMbDAwY3BiYVI1eloxdTBDMDhwb3BDU24z?= =?utf-8?B?eGI1Ti94R0VxVlhWYkNXWURiRmpPWWgrKy9MdlAzQWlpTzBnblNDVWg0cW0r?= =?utf-8?B?RjZRR2NxMW5hN1l4NXY0T280UTdQU1pXcFhPeE1VWStoTnFEcVdXYmpJNnQv?= =?utf-8?B?VWNHVERjQnhURGkvVHRlU29xaStYemZ3NmNCOFBUcDBERWcxR3R2Yy9QeHE3?= =?utf-8?B?TG5pVUpyaDNmVTdDdWVCWm5rWGY4eDNrQ0JVRkFmVC9ueDhsTGpHVHJxQktx?= =?utf-8?B?Mk5udEFLTHR1ZVI3dURaWXNXMzNBZkdzNHVDeGd5U1RQMncwdHFjNEJyeVRi?= =?utf-8?B?QjRaeDMwK1pxVHUralUrYWR5dTlrRUR0Sk5hUkFLNWs4VWVZL2VRMFE1QjFQ?= =?utf-8?B?M2xmMzhMSUhIYTZwRERTaE5rOXdBdUdFWm00aEZSSlVUUDhic0k0QTFydHB1?= =?utf-8?B?Z3pkRmhEemtYeVBKM3JmODdkWE42RC9TLzVETXNSMHFlcWtUSmxhRG9oL3Vi?= =?utf-8?B?R0tveHlmTGNyWjhaeWhWVmRTcVo2Ym9PR0hkOGFFc1pOaStrNHhyMlJMazJR?= =?utf-8?B?Q3dWdVRmaEd1STNmdVZUb0hpcVFBPT0=?= 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)(36860700013)(82310400026)(1800799024)(376014)(7416014)(30052699003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: WYjU6rhazA5W9jTQLSduIhGTGs8kQBIwniko9c4/XfTxYDqkW5/N6glwDP7UyaLe1gADHT4A4BFI/D1Xkv0SNvX/EdMLANGBO6buxqijkrcwnxjXYdfD4PIgV4jZ+tZZGHPkdNMCAGYp6U3xfX44qH1Tj9D1xjCHBS06SGquzZ/4HpmV1H/FTb3eKGe5oKC+ds7U6w/BQzN+ag8b07nu6/1FRyOuuba8FqpY1PWdFuCmmMa1BD2EpPz4ZqPo8qolBLCO7mhGFSNT6ExTo23YUOKQJ9TfTOSaInrTpANRihdUEJKDK7EaiNEW4FHF0Na6TnLTSGEB5SIsbK//9uTlQPlKgpENKTQsvOXqTFKQ2F+QwBw3zDdSz1ICxwJpvCF8X5ZHLBT87HYuyshNpIhGyPJiJ2aPbaiOX6Fct+IrK1AzZavmnjZtvh8i3ToUIibW X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Feb 2026 16:52:56.3982 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 1bb1ca9a-b318-413e-58aa-08de67fbacaf 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: MW1PEPF0001615C.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB6038 Hello Peter, On 2/9/2026 9:17 PM, Peter Zijlstra wrote: > On Wed, Feb 04, 2026 at 03:45:58PM +0530, K Prateek Nayak wrote: > >> # Overflow on enqueue >> >> <...>-102371 [255] ... : __enqueue_entity: Overflowed cfs_rq: >> <...>-102371 [255] ... : dump_h_overflow_cfs_rq: cfs_rq: depth(0) weight(90894772) nr_queued(2) sum_w_vruntime(0) sum_weight(0) zero_vruntime(701164930256050) sum_shift(0) avg_vruntime(701809615900788) >> <...>-102371 [255] ... : dump_h_overflow_entity: se: weight(3508) vruntime(701809615900788) slice(2800000) deadline(701810568648095) curr?(1) task?(1) <-------- cfs_rq->curr >> <...>-102371 [255] ... : __enqueue_entity: Overflowed se: >> <...>-102371 [255] ... : dump_h_overflow_entity: se: weight(90891264) vruntime(701808975077099) slice(2800000) deadline(701808975109401) curr?(0) task?(0) <-------- new se > > So I spend a whole time trying to reproduce the splat, but alas. > > That said, I did spot something 'funny' in the above, note that > zero_vruntime and avg_vruntime/curr->vruntime are significantly apart. > That is not something that should happen. zero_vruntime is supposed to > closely track avg_vruntime. > > That lead me to hypothesise that there is a problem tracking > zero_vruntime when there is but a single runnable task, and sure > enough, I could reproduce that, albeit not at such a scale as to lead to > such problems (probably too much noise on my machine). > > I ended up with the below; and I've already pushed out a fresh > queue/sched/core. Could you please test again? Thank you for looking into this. I'll merge this onto tip:sched/urgent and take it for a spin overnight like last time with PARANOID_AVG and see if the sum_shifts increment this time around. Will report back tomorrow on the status. As for the patch itself, I'll take a look at it tomorrow - limited by my drowsiness at the moment :-) -- Thanks and Regards, Prateek