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Wed, 11 Nov 2026 08:03:58 -0800 (PST) Received: from fedora ([2.35.201.240]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4ba08de826asm49553615e9.0.2026.11.11.08.03.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Nov 2026 08:03:56 -0800 (PST) From: Francesco Nigro To: K Prateek Nayak Cc: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Mike Galbraith , Mario Limonciello , Huang Rui , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [REPORT] sched: ITMT + DELAY_DEQUEUE: woken task waits ~1 ms behind another task on the preferred CPU while allowed CPUs are idle Date: Wed, 11 Nov 2026 17:03:33 +0100 Message-ID: <20261111160333.2206028-1-nigro.fra@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <99366157-08b9-411f-b180-fa61bc5f5002@amd.com> References: <20261103154603.1893325-1-nigro.fra@gmail.com> <5af4860d-096a-4e9d-a3b3-0b8277924146@amd.com> <20261105081245.81773-1-nigro.fra@gmail.com> <99366157-08b9-411f-b180-fa61bc5f5002@amd.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Thu, 2026-11-05 at 14:04 +0530, K Prateek Nayak wrote: > I'm having a hard time understanding why asym_active_balance() would > trigger before worker 482 blocks Sorry, that is my trimming: the "blocks" row is 482's context switch. The raw events (perf script on the same recording): .654331 [6] 482 sched_stat_runtime runtime=792910 [ns] .654334 [6] 482 sched_waking comm=migration/7 .654337 [6] 482 sched_switch 482 S ==> swapper/6 .654338 [7] 481 sched_switch 481 R ==> migration/7 .654341 [7] migration/7 sched_migrate_task 481 orig_cpu=7 dest_cpu=6 .654345 [6] swapper/6 sched_switch swapper/6 R ==> 481 Thanks, Franz