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

["Anirban, Sk" <sk.anirban@xxxxxxxxx>]

On 09-01-2025 16:45, Nilawar, Badal wrote:

On 09-01-2025 15:50, Nilawar, Badal wrote:

On 09-01-2025 15:00, sk.anirban@xxxxxxxxx wrote:

From: Sk Anirban <sk.anirban@xxxxxxxxx>

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@xxxxxxxxx>
Reviewed-by: Riana Tauro <riana.tauro@xxxxxxxxx>
---
 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 seeing rps_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

    The measure_power() function is being used by slpc also, as slpc is
    not passing the raw frequency it may cause issue. So the plan is to
    create independent function to measure power for slpc, and for rps I
    will be using read_cagf() to calculate the avg.
    
    Regards,
    Anirban

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;
 		}