[Intel-gfx] [PATCH 3/8] drm/i915/execlists: Suppress redundant preemption

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-01-29 11:15:35)
> 
> On 29/01/2019 08:58, Chris Wilson wrote:
> > On unwinding the active request we give it a small (limited to internal
> > priority levels) boost to prevent it from being gazumped a second time.
> > However, this means that it can be promoted to above the request that
> > triggered the preemption request, causing a preempt-to-idle cycle for no
> 
> How can it go higher? Only because I915_PRIORITY_NEWCLIENT is higher 
> than I915_PRIORITY_WAIT? In that case would re-ordering those help? I 
> don't remember if there was a reason for the current order.

Yes. There's more reasons later (media-bench is quite insistent about
this ;).

You were quite adamant in insisting that WAIT be the most minor of
boosts :)
-Chris