Re: [PATCH V2] thermal: power_allocator: Avoid overwriting PID coefficients from setup time

[Lukasz Luba]

Hi Di,

On 2/4/24 02:55, Di Shen wrote:
> Hi Lukasz,
>
> On Thu, Jan 25, 2024 at 2:24 PM Di Shen <di.shen@xxxxxxxxxx> wrote:
> > When the PID coefficients k_* are set via sysfs before the IPA
> > algorithm is triggered then the coefficients would be overwritten after
> > IPA throttle() is called. The old configuration values might be
> > different than the new values estimated by the IPA internal algorithm.
> >
> > There might be a time delay when this overwriting happens. It
> > depends on the thermal zone temperature value. The temperature value
> > needs to cross the first trip point value then IPA algorithms start
> > operating. Although, the PID coefficients setup time should not be
> > affected or linked to any later operating phase and values must not be
> > overwritten.
> >
> > This patch initializes params->sustainable_power when the governor
> > binds to thermal zone to avoid overwriting k_*. The basic function won't
> > be affected, as the k_* still can be estimated if the sustainable_power
> > is modified.
> >
> > Signed-off-by: Di Shen <di.shen@xxxxxxxxxx>
> > ---
> >   drivers/thermal/gov_power_allocator.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
> > index 81e061f183ad..1b17dc4c219c 100644
> > --- a/drivers/thermal/gov_power_allocator.c
> > +++ b/drivers/thermal/gov_power_allocator.c
> > @@ -711,6 +711,8 @@ static int power_allocator_bind(struct thermal_zone_device *tz)
> >
> >          if (!tz->tzp->sustainable_power)
> >                  dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");
> > +       else
> > +               params->sustainable_power = tz->tzp->sustainable_power;
> >
> >          estimate_pid_constants(tz, tz->tzp->sustainable_power,
> >                                 params->trip_switch_on,
> > --
> > 2.17.1
>
> Any comments on patchv2?
> Looking forward to hearing from you. Thanks!

My apologies I was out-of-office.

That v2 patch looks good. Although, please resend it as a new
message, not as a response to the v1. In that way it's easier to
pick it up by maintainers. You can use a tag:
[RESEND][PATCH v2] .....

You can add
Reviewed-by: Lukasz Luba <lukasz.luba@xxxxxxx>

Regards,
Lukasz