[Intel-gfx] [PATCH 6/6] drm/i915: Priority boost for waiting clients

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-08-06 10:53:52)
> 
> On 06/08/2018 09:30, Chris Wilson wrote:
> > Latency is in the eye of the beholder. In the case where a client stops
> > and waits for the gpu, give that request chain a small priority boost
> > (not so that it overtakes higher priority clients, to preserve the
> > external ordering) so that ideally the wait completes earlier.
> 
> Going back to my comments made against the new clients boost patch - 
> perhaps if you make it that preemption is not triggered for within 
> internal priority delta maybe it is all acceptable. Not sure how much of 
> the positive effect you observed remains though.

That entirely defeats the point of being able to preempt within the same
user priority; so no more "fairness" wrt FQ_CODEL and no more cheating
here.
-Chris