lkml.org 
[lkml]   [2020]   [Oct]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 2/2] thermal: power allocator: change how estimation code is called
From
Date
Hi Daniel,

On 10/13/20 5:41 PM, Daniel Lezcano wrote:
> On 09/10/2020 15:58, Lukasz Luba wrote:
>> The sustainable power value might come from the Device Tree or can be
>> estimated in run time. There is no need to estimate every time when the
>> governor is called and temperature is high. Instead, store the estimated
>> value and make it available via standard sysfs interface so it can be
>> checked from the user-space. Re-invoke the estimation only in case the
>> sustainable power was set to 0. Apart from that the PID coefficients
>> are not going to be force updated thus can better handle sysfs settings.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
>> ---
>
> [ ... ]
>
>> -static void estimate_pid_constants(struct thermal_zone_device *tz,
>> - u32 sustainable_power, int trip_switch_on,
>> - int control_temp, bool force)
>> +static void estimate_tzp_constants(struct thermal_zone_device *tz,
>> + int trip_switch_on, int control_temp)
>> {
>> - int ret;
>> - int switch_on_temp;
>> u32 temperature_threshold;
>> + int switch_on_temp;
>> + bool force = false;
>> + int ret;
>> s32 k_i;
>>
>> + if (!tz->tzp->sustainable_power) {
>> + tz->tzp->sustainable_power = estimate_sustainable_power(tz);
>> + force = true;
>> + dev_info(&tz->device, "power_allocator: estimating sust. power and PID constants\n");
>> + }
>> +
>> ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp);
>> if (ret)
>> switch_on_temp = 0;
>>
>> temperature_threshold = control_temp - switch_on_temp;
>> /*
>> - * estimate_pid_constants() tries to find appropriate default
>> + * estimate_tzp_constants() tries to find appropriate default
>> * values for thermal zones that don't provide them. If a
>> * system integrator has configured a thermal zone with two
>> * passive trip points at the same temperature, that person
>> @@ -151,11 +151,11 @@ static void estimate_pid_constants(struct thermal_zone_device *tz,
>> return;
>>
>> if (!tz->tzp->k_po || force)
>> - tz->tzp->k_po = int_to_frac(sustainable_power) /
>> + tz->tzp->k_po = int_to_frac(tz->tzp->sustainable_power) /
>> temperature_threshold;
>>
>> if (!tz->tzp->k_pu || force)
>> - tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /
>> + tz->tzp->k_pu = int_to_frac(2 * tz->tzp->sustainable_power) /
>> temperature_threshold;
>>
>> if (!tz->tzp->k_i || force) {
>> @@ -193,19 +193,13 @@ static u32 pid_controller(struct thermal_zone_device *tz,
>> {
>> s64 p, i, d, power_range;
>> s32 err, max_power_frac;
>> - u32 sustainable_power;
>> struct power_allocator_params *params = tz->governor_data;
>>
>> max_power_frac = int_to_frac(max_allocatable_power);
>>
>> - if (tz->tzp->sustainable_power) {
>> - sustainable_power = tz->tzp->sustainable_power;
>> - } else {
>> - sustainable_power = estimate_sustainable_power(tz);
>> - estimate_pid_constants(tz, sustainable_power,
>> - params->trip_switch_on, control_temp,
>> - true);
>> - }
>> + if (!tz->tzp->sustainable_power)
>> + estimate_tzp_constants(tz, params->trip_switch_on,
>> + control_temp);
>
> The changes in this patch are appropriate and make sense but they are
> not done at the right place.
>
> estimate_tzp_constants() must be called when sustainable_power is
> updated via DT/init or sysfs.
>
> Keeping a function to estimate the sustainable power and another one to
> estimate the k_* separated would be more clear.
>
> Actually the confusion is coming from when the pid constants are
> computed, I suggest moving the initialization of k_* out of this
> function and killing the 'force' test.
>
>
> [ ... ]
>
>

Thank you for the review. I will re-write the patch
and address your suggestion.

Regards,
Lukasz

\
 
 \ /
  Last update: 2020-10-29 10:25    [W:0.118 / U:0.312 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site