Re: [Intel-gfx] [PATCH 8/9] drm/i915/pmu: Split reading engine and other events into helpers

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 30/03/2023 01:41, Umesh Nerlige Ramappa wrote:
> Split the event reading function into engine and other helpers.

What, why and how please, third bit not being needed in this case. :)

> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_pmu.c | 93 ++++++++++++++++++---------------
>   1 file changed, 52 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> index 40ce1dc00067..9bd9605d2662 100644
> --- a/drivers/gpu/drm/i915/i915_pmu.c
> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> @@ -641,58 +641,69 @@ static u64 read_sample_us(struct i915_pmu *pmu, unsigned int gt_id, int sample)
>   	return div_u64(read_sample(pmu, gt_id, sample), USEC_PER_SEC);
>   }
>   
> -static u64 __i915_pmu_event_read(struct perf_event *event)
> +static u64 __i915_pmu_event_read_engine(struct perf_event *event)
>   {
> -	struct drm_i915_private *i915 =
> -		container_of(event->pmu, typeof(*i915), pmu.base);
> -	struct i915_pmu *pmu = &i915->pmu;
> +	struct drm_i915_private *i915 = container_of(event->pmu, typeof(*i915), pmu.base);

Liking the over 80 look, if you insist. :)

> +	u8 sample = engine_event_sample(event);
> +	struct intel_engine_cs *engine;
>   	u64 val = 0;
>   
> -	if (is_engine_event(event)) {
> -		u8 sample = engine_event_sample(event);
> -		struct intel_engine_cs *engine;
> -
> -		engine = intel_engine_lookup_user(i915,
> -						  engine_event_class(event),
> -						  engine_event_instance(event));
> +	engine = intel_engine_lookup_user(i915,
> +					  engine_event_class(event),
> +					  engine_event_instance(event));
>   
> -		if (drm_WARN_ON_ONCE(&i915->drm, !engine)) {
> -			/* Do nothing */
> -		} else if (sample == I915_SAMPLE_BUSY &&
> -			   intel_engine_supports_stats(engine)) {
> -			ktime_t unused;
> +	if (drm_WARN_ON_ONCE(&i915->drm, !engine)) {
> +		/* Do nothing */
> +	} else if (sample == I915_SAMPLE_BUSY &&
> +		   intel_engine_supports_stats(engine)) {
> +		ktime_t unused;
>   
> -			val = ktime_to_ns(intel_engine_get_busy_time(engine,
> -								     &unused));
> -		} else {
> -			val = engine->pmu.sample[sample].cur;
> -		}
> +		val = ktime_to_ns(intel_engine_get_busy_time(engine,
> +							     &unused));
>   	} else {
> -		const unsigned int gt_id = config_gt_id(event->attr.config);
> -		const u64 config = config_counter(event->attr.config);
> -
> -		switch (config) {
> -		case I915_PMU_ACTUAL_FREQUENCY:
> -			val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_ACT);
> -			break;
> -		case I915_PMU_REQUESTED_FREQUENCY:
> -			val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_REQ);
> -			break;
> -		case I915_PMU_INTERRUPTS:
> -			val = READ_ONCE(pmu->irq_count);
> -			break;
> -		case I915_PMU_RC6_RESIDENCY:
> -			val = get_rc6(i915->gt[gt_id]);
> -			break;
> -		case I915_PMU_SOFTWARE_GT_AWAKE_TIME:
> -			val = ktime_to_ns(intel_gt_get_awake_time(to_gt(i915)));
> -			break;
> -		}
> +		val = engine->pmu.sample[sample].cur;
>   	}
>   
>   	return val;
>   }
>   
> +static u64 __i915_pmu_event_read_other(struct perf_event *event)
> +{
> +	struct drm_i915_private *i915 = container_of(event->pmu, typeof(*i915), pmu.base);
> +	const unsigned int gt_id = config_gt_id(event->attr.config);
> +	const u64 config = config_counter(event->attr.config);
> +	struct i915_pmu *pmu = &i915->pmu;
> +	u64 val = 0;
> +
> +	switch (config) {
> +	case I915_PMU_ACTUAL_FREQUENCY:
> +		val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_ACT);
> +		break;
> +	case I915_PMU_REQUESTED_FREQUENCY:
> +		val = read_sample_us(pmu, gt_id, __I915_SAMPLE_FREQ_REQ);
> +		break;
> +	case I915_PMU_INTERRUPTS:
> +		val = READ_ONCE(pmu->irq_count);
> +		break;
> +	case I915_PMU_RC6_RESIDENCY:
> +		val = get_rc6(i915->gt[gt_id]);
> +		break;
> +	case I915_PMU_SOFTWARE_GT_AWAKE_TIME:
> +		val = ktime_to_ns(intel_gt_get_awake_time(to_gt(i915)));
> +		break;
> +	}
> +
> +	return val;
> +}
> +
> +static u64 __i915_pmu_event_read(struct perf_event *event)
> +{
> +	if (is_engine_event(event))
> +		return __i915_pmu_event_read_engine(event);
> +	else
> +		return __i915_pmu_event_read_other(event);
> +}
> +
>   static void i915_pmu_event_read(struct perf_event *event)
>   {
>   	struct drm_i915_private *i915 =

No real complaints - it is tidier and more readable. Just drop a note in 
the commit that is why and:

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Regards,

Tvrtko