linux-kernel - Re: [PATCH v4 0/2] pmdomain: Improve idle state selection for CPUs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAPDyKFqtJDoFwCB8_GG1XUVmmbQw=Wc+CEfuC0V3qqB6Xz3YtA@mail.gmail.com>
Date: Fri, 14 Nov 2025 17:16:33 +0100
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J . Wysocki" <rafael@...nel.org>, Thomas Gleixner <tglx@...utronix.de>
Cc: Mark Rutland <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>, 
	Maulik Shah <quic_mkshah@...cinc.com>, Sudeep Holla <sudeep.holla@....com>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, Vincent Guittot <vincent.guittot@...aro.org>, 
	Ben Horgan <ben.horgan@....com>, linux-pm@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/2] pmdomain: Improve idle state selection for CPUs

On Wed, 5 Nov 2025 at 10:54, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
> Platforms using the genpd governor for CPUs are relying on it to find the most
> optimal idle state for a group of CPUs. Although, observations tells us that
> there are some significant improvement that can be made around this.
>
> These improvement are based upon allowing us to take pending IPIs into account
> for the group of CPUs that the genpd governor is in control of. If there is
> pending IPI for any of these CPUs, we should not request an idle state that
> affects the group, but rather pick a shallower state that affects only the CPU.
>
> More details are available in the commit messages for each patch.
>
> Kind regards
> Ulf Hansson
>
> Ulf Hansson (2):
>   smp: Introduce a helper function to check for pending IPIs
>   pmdomain: Extend the genpd governor for CPUs to account for IPIs
>
>  drivers/pmdomain/governor.c | 20 +++++++++++++-------
>  include/linux/smp.h         |  5 +++++
>  kernel/smp.c                | 22 ++++++++++++++++++++++
>  3 files changed, 40 insertions(+), 7 deletions(-)
>
> --
> 2.43.0
>

FYI, I have queued this for v6.19 via my pmdomain tree. Please let me
know if you have any further comments or objections to this!

Thomas, thanks for your guidance around this topic!

Kind regards
Uffe