linux-kernel - Re: [PATCH resend 1/2] sched: psi: loosen clock sync between scheduler and aggregator

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Message-ID: <aYJiVzHpLcIXusrh@cmpxchg.org>
Date: Tue, 3 Feb 2026 16:02:15 -0500
From: Johannes Weiner <hannes@...xchg.org>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Suren Baghdasaryan <surenb@...gle.com>, Ingo Molnar <mingo@...nel.org>,
	Chengming Zhou <chengming.zhou@...ux.dev>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	John Stultz <jstultz@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH resend 1/2] sched: psi: loosen clock sync between
 scheduler and aggregator

On Tue, Feb 03, 2026 at 10:38:09AM -0500, Johannes Weiner wrote:
> Yes. The backward motion is what caused the multi-second errors that
> immediately shift even the long-term averages. Those are blatantly
> noticable and cause practical issues. And notably, these were the ONLY
> issue anyone reported against 3840cbe24cf0 in three years.

Grr.

"[...] reported against df77430639c9 ("psi: Reduce calls to
ched_clock() in psi") in three years", of course.