[PATCH v2] drm/i915/selftests: Correct frequency handling in RPS power measurement

[Nilawar, Badal]

On 09-01-2025 15:50, Nilawar, Badal wrote:
>
>
> On 09-01-2025 15:00, sk.anirban at intel.com wrote:
>> From: Sk Anirban<sk.anirban at intel.com>
>>
>> Fix the frequency calculation by ensuring it is adjusted
>> only once during power measurement. Update live_rps_power test
>> to use the correct frequency values for logging and comparison.
>>
>> v2:
>>    - Improved frequency logging (Riana)
>>
>> Signed-off-by: Sk Anirban<sk.anirban at intel.com>
>> Reviewed-by: Riana Tauro<riana.tauro at intel.com>
>> ---
>>   drivers/gpu/drm/i915/gt/selftest_rps.c | 11 ++++++-----
>>   1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
>> index c207a4fb03bf..e515d7eb628a 100644
>> --- a/drivers/gpu/drm/i915/gt/selftest_rps.c
>> +++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
>> @@ -1126,6 +1126,7 @@ static u64 measure_power_at(struct intel_rps *rps, int *freq)
>>   {
>>   	*freq = rps_set_check(rps, *freq);
>>   	msleep(100);
>> +	*freq = intel_gpu_freq(rps, *freq);
> I am seeingrps_set_check will wait till act freq become desired freq, in case of 
> timeout act freq could be different. I think it would be good to check 
> freq returned by rps_set_check is expected freq if not then read freq 
> again after msleep.

Please ignore above comments, I got your code. You are applying freq 
multiplier before passing to measure_power. While this approach works 
fine, I recommend fixing measure_power() by using read_cagf() instead of 
intel_rps_read_actual_frequency().
Add Fixes: ac4e8560248f ("drm/i915/selftests: Add helper function 
measure_power") in commit message.

Regards,
Badal

> Regards, Badal
>
>>   	return measure_power(rps, freq);
>>   }
>>   
>> @@ -1202,13 +1203,13 @@ int live_rps_power(void *arg)
>>   
>>   		pr_info("%s: min:%llumW @ %uMHz, max:%llumW @ %uMHz\n",
>>   			engine->name,
>> -			min.power, intel_gpu_freq(rps, min.freq),
>> -			max.power, intel_gpu_freq(rps, max.freq));
>> +			min.power, min.freq,
>> +			max.power, max.freq);
>>   
>>   		if (10 * min.freq >= 9 * max.freq) {
>> -			pr_notice("Could not control frequency, ran at [%d:%uMHz, %d:%uMhz]\n",
>> -				  min.freq, intel_gpu_freq(rps, min.freq),
>> -				  max.freq, intel_gpu_freq(rps, max.freq));
>> +			pr_notice("Could not control frequency, ran at [%uMHz, %uMhz]\n",
>> +				  min.freq,
>> +				  max.freq);
>>   			continue;
>>   		}
>>   
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