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[86.169.41.76]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43796ac8d82sm54220171f8f.31.2026.02.19.19.41.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Feb 2026 19:41:28 -0800 (PST) Date: Fri, 20 Feb 2026 03:41:27 +0000 From: Qais Yousef To: Tim Chen Cc: Peter Zijlstra , Ingo Molnar , K Prateek Nayak , "Gautham R . Shenoy" , Vincent Guittot , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Madadi Vineeth Reddy , Hillf Danton , Shrikanth Hegde , Jianyong Wu , Yangyu Chen , Tingyin Duan , Vern Hao , Vern Hao , Len Brown , Aubrey Li , Zhao Liu , Chen Yu , Chen Yu , Adam Li , Aaron Lu , Tim Chen , Josh Don , Gavin Guo , Libo Chen , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 00/21] Cache Aware Scheduling Message-ID: <20260220034127.ptmnnoisgg3vnxj4@airbuntu> References: <20260219140828.a7pyzupun7lsdw34@airbuntu> <20260219144108.GI1282955@noisy.programming.kicks-ass.net> <20260219194845.jqu5ydhid7csukpk@airbuntu> <2822d23a5f3601073b95627075f7d1eac20e9694.camel@linux.intel.com> 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: <2822d23a5f3601073b95627075f7d1eac20e9694.camel@linux.intel.com> On 02/19/26 13:47, Tim Chen wrote: > > > > I know this changes the direction being made here; but I strongly believe the > > > > right way is to extend wake up path rather than lump it solely in LB (IIUC). > > > > > > You're really going to need both, and LB really is the more complicated > > > part. On a busy/loaded system, LB will completely wreck things for you > > > if it doesn't play ball. > > > > Yes I wasn't advocating for wake up both only of course. But I didn't read all > > the details but I saw no wake up done. > > > > And generally as I think I have been indicating here and there; we do need to > > unify the wakeup and LB decision tree. With push lb this unification become > > a piece of cake if the wakeup path already handles the case. The current LB > > is a big beast. And will be slow to react for many systems. > > I think as long as we have up to date information on load at the time of push > in push lb, so we don't cause over aggregation and too much load imbalance, > it will be viable to make such aggregation at wake up. IMHO I see people are constantly tripping over task placement being too simple and need smarter decision making process. I think Vincent's proposal is spot on to help us handle all these situations simply with the added bonus of it being a lot more reactive. Going down this rabbit hole is worthwhile and will benefit us in the long run to handle more cases.