linux-kernel - Re: stable: commit "cpuidle: menu: Avoid discarding useful information" causes regressions

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Message-ID: <08529809-5ca1-4495-8160-15d8e85ad640@arm.com>
Date: Tue, 14 Oct 2025 10:50:02 +0100
From: Christian Loehle <christian.loehle@....com>
To: Sergey Senozhatsky <senozhatsky@...omium.org>,
 "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>,
 Sasha Levin <sashal@...nel.org>, Daniel Lezcano <daniel.lezcano@...aro.org>,
 linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
 Tomasz Figa <tfiga@...omium.org>, stable@...r.kernel.org
Subject: Re: stable: commit "cpuidle: menu: Avoid discarding useful
 information" causes regressions

On 10/14/25 08:43, Sergey Senozhatsky wrote:
> Hello,
> 
> We are observing performance regressions (cpu usage, power
> consumption, dropped frames in video playback test, etc.)
> after updating to recent stable kernels.  We tracked it down
> to commit 3cd2aa93674e in linux-6.1.y and commit 3cd2aa93674
> in linux-6.6.y ("cpuidle: menu: Avoid discarding useful information",
> upstream commit 85975daeaa4).
> 
> Upstream fixup fa3fa55de0d ("cpuidle: governors: menu: Avoid using
> invalid recent intervals data") doesn't address the problems we are
> observing.  Revert seems to be bringing performance metrics back to
> pre-regression levels.

Any details would be much appreciated.
How do the idle state usages differ with and without
"cpuidle: menu: Avoid discarding useful information"?
What do the idle states look like in your platform?