[PATCH v4 0/2] pmdomain: Improve idle state selection for CPUs

Ulf Hansson posted 2 patches 1 month, 2 weeks ago
drivers/pmdomain/governor.c | 20 +++++++++++++-------
include/linux/smp.h         |  5 +++++
kernel/smp.c                | 22 ++++++++++++++++++++++
3 files changed, 40 insertions(+), 7 deletions(-)
[PATCH v4 0/2] pmdomain: Improve idle state selection for CPUs
Posted by Ulf Hansson 1 month, 2 weeks ago
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
Re: [PATCH v4 0/2] pmdomain: Improve idle state selection for CPUs
Posted by Ulf Hansson 1 month ago
On Wed, 5 Nov 2025 at 10:54, Ulf Hansson <ulf.hansson@linaro.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