On 24/05/2023 22:46, Dixit, Ashutosh wrote:
On Wed, 24 May 2023 02:12:31 -0700, Andrzej Hajda wrote:
Hi Andrzej,
On 23.05.2023 17:19, Ashutosh Dixit wrote:
pmu_needs_timer() keeps the timer running even when GT is parked,
ostensibly to sample requested/actual frequencies. However
frequency_sample() has the following:
/* Report 0/0 (actual/requested) frequency while parked. */
if (!intel_gt_pm_get_if_awake(gt))
return;
The above code prevents frequencies to be sampled while the GT is
parked. So we might as well turn off the sampling timer itself in this
case and save CPU cycles/power.
v2: Instead of turning freq bits off, return false, since no counters will
run after this change when GT is parked (Tvrtko)
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_pmu.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index a814583e19fd7..b47d890d4ada1 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -144,6 +144,10 @@ static bool pmu_needs_timer(struct i915_pmu *pmu, bool gpu_active)
struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
u32 enable;
+ /* When GPU is idle, at present no counters need to run */
+ if (!gpu_active)
+ return false;
+
What is then purpose of calling pmu_needs_timer with 2nd arg false?
Why not just replace all occurrences of pmu_needs_timer(.., false) with
false? And remove the 2nd argument.
OK, this didn't seem unreasonable so I went ahead and made this change in
Patch v3. Copying Tvrtko too in case he prefers v2 for any reason. Please
review.
It is all fine by me (the latest version and all)!
Regards,
Tvrtko
