linux-kernel - Re: [PATCH v8 0/3] sched/fair: Optimize cfs_rq and sched_entity allocation for better data locality

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Message-ID: <03488c43-2dc4-4ede-a489-b196e1426921@amd.com>
Date: Thu, 22 Jan 2026 14:33:20 +0530
From: K Prateek Nayak <kprateek.nayak@....com>
To: Zecheng Li <zli94@...u.edu>, Ingo Molnar <mingo@...hat.com>, "Peter
 Zijlstra" <peterz@...radead.org>, Juri Lelli <juri.lelli@...hat.com>,
	"Vincent Guittot" <vincent.guittot@...aro.org>
CC: Dietmar Eggemann <dietmar.eggemann@....com>, Steven Rostedt
	<rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>, Mel Gorman
	<mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>, Rik van Riel
	<riel@...riel.com>, Chris Mason <clm@...com>, Madadi Vineeth Reddy
	<vineethr@...ux.ibm.com>, Xu Liu <xliuprof@...gle.com>, Blake Jones
	<blakejones@...gle.com>, Josh Don <joshdon@...gle.com>, Nilay Vaish
	<nilayvaish@...gle.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 0/3] sched/fair: Optimize cfs_rq and sched_entity
 allocation for better data locality

Hello Zecheng,

On 1/22/2026 2:03 AM, Zecheng Li wrote:
> Hi all,
> 
> This patch series improves CFS cache performance by allocating cfs_rq
> and sched_entity together in the per-cpu allocator. It allows for
> replacing the pointer arrays in task_group with a per-cpu offset.

I tested this with a cgroup stress test and haven't seen any splats.
Feel free to include:

Reviewed-by: K Prateek Nayak <kprateek.nayak@....com>
Tested-by: K Prateek Nayak <kprateek.nayak@....com>

Peter, I suppose you'll still need this with sched/flat since all
the intermediate sched_entities and cfs_rqs still l remain and
afaict co-locating sched_entity and the group cfs_rq can help since
prefetchers will very likely fetch the other when one of them is
accessed.

-- 
Thanks and Regards,
Prateek