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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 15.20.9745.21 via Frontend Transport; Tue, 31 Mar 2026 08:50:03 +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; Tue, 31 Mar 2026 03:50:03 -0500 Received: from [10.136.44.157] (10.180.168.240) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server id 15.2.2562.17 via Frontend Transport; Tue, 31 Mar 2026 03:49:59 -0500 Message-ID: <19667aac-99c4-40cf-bc0a-b1e6b9d32ede@amd.com> Date: Tue, 31 Mar 2026 14:19:54 +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 1/7] sched/fair: Fix zero_vruntime tracking To: Peter Zijlstra CC: John Stultz , , , , , , , , , , , , , , Suleiman Souhlal References: <20260219075840.162631716@infradead.org> <20260219080624.438854780@infradead.org> <20260330101018.GN3738786@noisy.programming.kicks-ass.net> <73dab51a-650f-4c82-9e73-13236b2a26c2@amd.com> <20260330144005.GP3738786@noisy.programming.kicks-ass.net> <20260330191108.GU2872@noisy.programming.kicks-ass.net> <20260331070822.GC3739027@noisy.programming.kicks-ass.net> <20260331071402.GN3739106@noisy.programming.kicks-ass.net> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20260331071402.GN3739106@noisy.programming.kicks-ass.net> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: qNJN0IjbRjqQSPCrxRGp3yO8xUMuXNUvLOHT2HmHpa3QUJfRWpwBremQ7OeCd5l2IbGk3dYugWYysmwQRbeTIzIFOCidoy1VMiw01IxMwupi+bhYTLybvi9IcDgDZshryUIHzWAgzFy+DuAccgRd1zXk4z4TIWDnSdC+TWlixbdmWnr6OKbOi9yGT0XN+tpAzKuHEvzq+KIh9+DF30Bj1/i5a2FPI3X0FWixm2HUgeqc0CmioB934LSrmB90ttj6TgiLOFFkANyGQKtsPqU6w85JTGaMh1NH8xl2cYEEcYbjfyqPL0MDr/fnZAfYpJIY96l8MnQ6yklLaFYZrwbFfCNAAMT0E1YDG9GUWVfUZKbyFhTOoX4lgynAO9+hm87XF3ntmDuR5lBVoq/zu2ey5UkTvIV9ClpPia5GYvYfIY5yWW9a1g6/RqvUUgI8kkSl X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Mar 2026 08:50:03.9429 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e776462f-b6ef-4e89-c882-08de8f028070 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: CH3PR12MB8283 On 3/31/2026 12:44 PM, Peter Zijlstra wrote: > On Tue, Mar 31, 2026 at 09:08:23AM +0200, Peter Zijlstra wrote: >> On Tue, Mar 31, 2026 at 06:08:27AM +0530, K Prateek Nayak wrote: >> >>> The above doesn't recover after a avg_vruntime(). Btw I'm running: >>> >>> nice -n 19 stress-ng --yield 32 -t 1000000s& >>> while true; do perf bench sched messaging -p -t -l 100000 -g 16; done >> >> And you're running that on a 16 cpu machine / vm ? > > W00t, it went b00m. Ok, let me go add some tracing. I could only repro it on baremetal after few hours but good to know it exploded effortlessly on your end! Was this a 16vCPU VM with the same recipe? -- Thanks and Regards, Prateek