[Intel-gfx] [PATCH 6/7] drm/i915/pmu: Add running counter

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-06-07 14:25:28)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> We add a PMU counter to expose the number of requests currently executing
> on the GPU.
> 
> This is useful to analyze the overall load of the system.
> 
> v2:
>  * Rebase.
>  * Drop floating point constant. (Chris Wilson)
> 
> v3:
>  * Change scale to 1024 for faster arithmetics. (Chris Wilson)
> 
> v4:
>  * Refactored for timer period accounting.
> 
> v5:
>  * Avoid 64-division. (Chris Wilson)
> 
> v6:
>  * Do fewer divisions by accumulating in qd.ns units. (Chris Wilson)
>  * Change counter scale to avoid multiplication in readout and increase
>    counter headroom.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

I can't spot any nits to pick. That means I actually have to review it
now, right?
-Chris