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[82.212.34.85]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48fffb9aac4sm352331825e9.9.2026.05.19.00.46.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 00:46:35 -0700 (PDT) Date: Tue, 19 May 2026 09:46:35 +0200 Message-ID: <06fa37519f4cd1c1f4d1903c37680ae1.tomge68@gmail.com> From: Tom Gebhardt To: Christian Loehle Cc: Qais Yousef , linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Vincent Guittot Subject: Re: [PATCH v2 00/13] sched/fair/schedutil: Better manage system response time In-Reply-To: References: <20260504020003.71306-1-qyousef@layalina.io> <20260515014250.tueinbuk7ldttdop@airbuntu> <32dea9123588227a02971341b22e84d3.tomge68@gmail.com> <28c59186-4ba0-44f4-b5b8-42f6f73cd3e6@arm.com> <318a4aaf404b66f7a04ed4d4a18d228a.tomge68@gmail.com> Content-Type: text/plain; charset=UTF-8 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Hi Christian, Thanks for trying to replicate -- and your result actually confirms the picture: without Peter's ttwu series, Vincent's fix has no measurable effect. That's consistent with what I see: the improvement from patch 12 / Vincent's fix only shows up *on top of* the ttwu patches, not standalone. So the interaction seems to be: ttwu patches alone → −22% vs. 6.6 at OC ttwu + util_est fix → −1.2% vs. 6.6 at OC (large recovery) vanilla 7.0 (no ttwu) → −26% vs. 6.6 at OC vanilla 7.0 + util_est → no significant change (your result) This suggests the ttwu series changes something in the dequeue path that exposes the util_est timing issue, and the fix only matters in that context. I would be happy to push the exact tree so you can reproduce it directly. However, I currently have a hardware issue with the Pi and cannot test or prepare the tree right now. I'll push it to GitHub as soon as I'm back up and let you know here. Tom