[PATCH] thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power

[PATCH] thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power

[Yu-Che Cheng]

divvy_up_power should use weighted_req_power instead of req_power to
calculate the granted_power. Otherwise, the granted_power may be
unexpected as the denominator total_req_power is weighted sum.

This is a mistake during the previous refactor.

Replace the req_power with weighted_req_power in divvy_up_power
calculation.

Fixes: 912e97c67cc3 ("thermal: gov_power_allocator: Move memory allocation out of throttle()")
Signed-off-by: Yu-Che Cheng <giver@chromium.org>
---
 drivers/thermal/gov_power_allocator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
index 3b644de3292e..3b626db55b2b 100644
--- a/drivers/thermal/gov_power_allocator.c
+++ b/drivers/thermal/gov_power_allocator.c
@@ -370,7 +370,7 @@ static void divvy_up_power(struct power_actor *power, int num_actors,
 
 	for (i = 0; i < num_actors; i++) {
 		struct power_actor *pa = &power[i];
-		u64 req_range = (u64)pa->req_power * power_range;
+		u64 req_range = (u64)pa->weighted_req_power * power_range;
 
 		pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,
 							  total_req_power);

---
base-commit: 2408a807bfc3f738850ef5ad5e3fd59d66168996
change-id: 20250218-fix-power-allocator-calc-f00b4ab650ba

Best regards,
-- 
Yu-Che Cheng <giver@chromium.org>

Re: [PATCH] thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power

[Rafael J. Wysocki]

On Wed, Feb 19, 2025 at 8:07 AM Yu-Che Cheng <giver@chromium.org> wrote:
>
> divvy_up_power should use weighted_req_power instead of req_power to
> calculate the granted_power. Otherwise, the granted_power may be
> unexpected as the denominator total_req_power is weighted sum.

Yes, this is what's happening, to my eyes.

> This is a mistake during the previous refactor.
>
> Replace the req_power with weighted_req_power in divvy_up_power
> calculation.
>
> Fixes: 912e97c67cc3 ("thermal: gov_power_allocator: Move memory allocation out of throttle()")
> Signed-off-by: Yu-Che Cheng <giver@chromium.org>
> ---
>  drivers/thermal/gov_power_allocator.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
> index 3b644de3292e..3b626db55b2b 100644
> --- a/drivers/thermal/gov_power_allocator.c
> +++ b/drivers/thermal/gov_power_allocator.c
> @@ -370,7 +370,7 @@ static void divvy_up_power(struct power_actor *power, int num_actors,
>
>         for (i = 0; i < num_actors; i++) {
>                 struct power_actor *pa = &power[i];
> -               u64 req_range = (u64)pa->req_power * power_range;
> +               u64 req_range = (u64)pa->weighted_req_power * power_range;
>
>                 pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,
>                                                           total_req_power);
>
> ---

And the fix looks good to me.

Lukasz, any concerns?

Re: [PATCH] thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power

[Lukasz Luba]

On 2/20/25 19:45, Rafael J. Wysocki wrote:
> On Wed, Feb 19, 2025 at 8:07 AM Yu-Che Cheng <giver@chromium.org> wrote:
>>
>> divvy_up_power should use weighted_req_power instead of req_power to
>> calculate the granted_power. Otherwise, the granted_power may be
>> unexpected as the denominator total_req_power is weighted sum.
> 
> Yes, this is what's happening, to my eyes.
> 
>> This is a mistake during the previous refactor.
>>
>> Replace the req_power with weighted_req_power in divvy_up_power
>> calculation.
>>
>> Fixes: 912e97c67cc3 ("thermal: gov_power_allocator: Move memory allocation out of throttle()")
>> Signed-off-by: Yu-Che Cheng <giver@chromium.org>
>> ---
>>   drivers/thermal/gov_power_allocator.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
>> index 3b644de3292e..3b626db55b2b 100644
>> --- a/drivers/thermal/gov_power_allocator.c
>> +++ b/drivers/thermal/gov_power_allocator.c
>> @@ -370,7 +370,7 @@ static void divvy_up_power(struct power_actor *power, int num_actors,
>>
>>          for (i = 0; i < num_actors; i++) {
>>                  struct power_actor *pa = &power[i];
>> -               u64 req_range = (u64)pa->req_power * power_range;
>> +               u64 req_range = (u64)pa->weighted_req_power * power_range;
>>
>>                  pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,
>>                                                            total_req_power);
>>
>> ---
> 
> And the fix looks good to me.
> 
> Lukasz, any concerns?

Good catch! It went through since the test didn't set different weights.

Thanks for the fix!

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Re: [PATCH] thermal: gov_power_allocator: Fix incorrect calculation in divvy_up_power

[Rafael J. Wysocki]

On Fri, Feb 21, 2025 at 11:35 AM Lukasz Luba <lukasz.luba@arm.com> wrote:
>
>
>
> On 2/20/25 19:45, Rafael J. Wysocki wrote:
> > On Wed, Feb 19, 2025 at 8:07 AM Yu-Che Cheng <giver@chromium.org> wrote:
> >>
> >> divvy_up_power should use weighted_req_power instead of req_power to
> >> calculate the granted_power. Otherwise, the granted_power may be
> >> unexpected as the denominator total_req_power is weighted sum.
> >
> > Yes, this is what's happening, to my eyes.
> >
> >> This is a mistake during the previous refactor.
> >>
> >> Replace the req_power with weighted_req_power in divvy_up_power
> >> calculation.
> >>
> >> Fixes: 912e97c67cc3 ("thermal: gov_power_allocator: Move memory allocation out of throttle()")
> >> Signed-off-by: Yu-Che Cheng <giver@chromium.org>
> >> ---
> >>   drivers/thermal/gov_power_allocator.c | 2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
> >> index 3b644de3292e..3b626db55b2b 100644
> >> --- a/drivers/thermal/gov_power_allocator.c
> >> +++ b/drivers/thermal/gov_power_allocator.c
> >> @@ -370,7 +370,7 @@ static void divvy_up_power(struct power_actor *power, int num_actors,
> >>
> >>          for (i = 0; i < num_actors; i++) {
> >>                  struct power_actor *pa = &power[i];
> >> -               u64 req_range = (u64)pa->req_power * power_range;
> >> +               u64 req_range = (u64)pa->weighted_req_power * power_range;
> >>
> >>                  pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,
> >>                                                            total_req_power);
> >>
> >> ---
> >
> > And the fix looks good to me.
> >
> > Lukasz, any concerns?
>
> Good catch! It went through since the test didn't set different weights.
>
> Thanks for the fix!
>
> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Applied as 6.14-rc material, thanks!