From: Peter Zijlstra <peterz@infradead.org>
To: Zicheng Qu <quzicheng315@gmail.com>
Cc: arighi@nvidia.com, brho@google.com, bsegall@google.com,
changwoo@igalia.com, dietmar.eggemann@arm.com, haoluo@google.com,
joshdon@google.com, juri.lelli@redhat.co, kprateek.nayak@amd.com,
linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@redhat.com,
quzicheng@huawei.com, rostedt@goodmis.org,
sched-ext@lists.linux.dev, tanghui20@huawei.com, tj@kernel.org,
vincent.guittot@linaro.org, void@manifault.com,
vschneid@redhat.com, zhangqiao22@huawei.com
Subject: Re: [PATCH v2] sched_ext: Rebuild fair weight on ext to fair switches
Date: Thu, 28 May 2026 11:25:35 +0200 [thread overview]
Message-ID: <20260528092535.GC343181@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <3c258a36-2b28-4221-b2b6-776a0b1693ab@gmail.com>
On Thu, May 28, 2026 at 10:53:54AM +0800, Zicheng Qu wrote:
> 2. Rebuilding `p->se.load` from fair's `switching_to` hook. This is the most
> natural place semantically, since the task is entering fair and fair
> prepares
> its own state before enqueue. My only concern was that, for non-ext -> fair
> paths, `__setscheduler_params()` may have already updated `p->se.load`
> through
> `set_load_weight(p, true)`, so calling `set_load_weight(p, false)`
> unconditionally here can be redundant logically. Functionally, though, it is
> harmless.
Right. We can worry about optimizing this if there's ever a report. I
don't expect this to be noticeable much. If anything, the PI code would
be the one to trip this most often I think.
next prev parent reply other threads:[~2026-05-28 9:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-26 13:52 [PATCH] sched_ext: Rebuild fair weight when disabling BPF scheduler Zicheng Qu
2026-05-26 17:20 ` Andrea Righi
2026-05-27 9:40 ` [PATCH v2] sched_ext: Rebuild fair weight on ext to fair switches quzicheng315
2026-05-27 11:26 ` Peter Zijlstra
2026-05-28 2:53 ` Zicheng Qu
2026-05-28 9:25 ` Peter Zijlstra [this message]
2026-05-28 13:12 ` [PATCH v3] sched/fair: Rebuild load weight when switching to fair quzicheng315
2026-05-28 14:27 ` Tejun Heo
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