linux-kernel - Re: scheduler performance regression since v6.11

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Message-ID: <20250512180846.GA25891@noisy.programming.kicks-ass.net>
Date: Mon, 12 May 2025 20:08:46 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Chris Mason <clm@...a.com>
Cc: linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
	dietmar.eggemann@....com, vschneid@...hat.com
Subject: Re: scheduler performance regression since v6.11

On Fri, May 09, 2025 at 09:49:55PM +0200, Peter Zijlstra wrote:
> 152 729288bc6856 kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
> 	average rps: 1936829.47
> 	average rps: 1950715.10
> 
> 153 84d265281d6c sched/pelt: Use rq_clock_task() for hw_pressure
> 	average rps: 2176857.32
> 	average rps: 2223004.23

So, a little more data on this.

The result appears stable, but reverting 729288bc6856 on master does not
seem to cure things.

OTOH, switching to performance governor completely cures things here.

My machine defaults to schedutil governor.

Chris, can you confirm -- or did we manage to find different issues?