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[86.135.101.43]) by smtp.gmail.com with ESMTPSA id f9-20020a05600c154900b0040c4be1af17sm19385495wmg.21.2023.12.15.14.57.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Dec 2023 14:57:19 -0800 (PST) Date: Tue, 12 Dec 2023 15:59:16 +0000 From: Qais Yousef To: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] sched/fair: Check a task has a fitting cpu when updating misfit Message-ID: <20231212155916.cqlgv5eypuvfom3n@airbuntu> References: <20231212154056.626978-1-qyousef@layalina.io> 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-Disposition: inline In-Reply-To: <20231212154056.626978-1-qyousef@layalina.io> On 12/12/23 15:40, Qais Yousef wrote: > Food for thoughts: should misfit cause balance_interval to double? This patch > will still be needed if the answer is yes to avoid unnecessary misfit-lb to > trigger repeatedly anyway. I should add, should balance_interval be capped to smaller values? Anything above 64ms looks too high to me, even 64ms for systems that need responsiveness can be considered too high. 16ms or 32ms look more reasonable to my (likely very) naive eyes :-) We should probably look at reducing TICK value as well. 1ms requires 3 failures to reach 8ms for example. But 4ms TICK requires one failure to go to 8ms. Maybe there's room to make the doubling logic more normalized. 3 failures on 4ms will reach 32ms. Cheers -- Qais Yousef