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[66.183.142.209]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8249e422d1dsm699564b3a.29.2026.02.10.21.21.20 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 Feb 2026 21:21:21 -0800 (PST) From: "Doug Smythies" To: "'Vincent Guittot'" , "'Peter Zijlstra'" Cc: "'K Prateek Nayak'" , , , , , , , , , , , , "Doug Smythies" 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> In-Reply-To: Subject: RE: [PATCH 0/4] sched: Various reweight_entity() fixes Date: Tue, 10 Feb 2026 21:21:24 -0800 Message-ID: <002501dc9b16$442a7050$cc7f50f0$@telus.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Content-Language: en-ca Thread-Index: AQK5IwR5loYZhW90rhLC3Nnzvp6wgAGWA92PAlBHLF4B5k73QgEcsVRAAlcnOhYDFmLm87NhKs6w On 2026.02.10 12:52 Vincent Guittot wrote: > On Mon, 9 Feb 2026 at 16:47, Peter Zijlstra wrote: >> On Wed, Feb 04, 2026 at 03:45:58PM +0530, K Prateek Nayak wrote: > ... delete ... > This patch w/ the patchset on top of tip/sched/core create regressions > for hackbench (tbench doesn't seem to be impacted) on my dragonboard > rb5 > All hackbench tests are regressing. Some results below ... > hackbench 8 group process socket > 0.650(+/-1%) vs 2.361(+/-8.8%) : -263% ... Very interesting. I only know of the Phoronix version of hackbench. I ran what I believe to be a similar scenario to yours: 10 test runs each (the default is 3): Kernel 6.19-rc8: 23.228 seconds average, deviation 0.39% Kernel 6.19-rc8-pz-v2: 85.755 seconds average, deviation 3.33% 269% regression. (very similar to Vicent's results) System: Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz, 6 cores 12 CPUs. CPU frequency scaling driver: intel_pstate. CPU frequency scaling governor: powersave. HWP: enabled. idle governor teo.