[Intel-gfx] [RFC] drm/i915: Skip BSW display interrupt checks if we have a GT interrupt

[Chris Wilson]

On Fri, Jan 20, 2017 at 10:15:09AM +0000, Chris Wilson wrote:
> GT interrupts are very, very frequent as they are used for submitting
> every request to the hardware (thanks be to execlists). Given their
> prevalence and the comparity rarity of display interrupts, if we do
> receive an IRQ and we process a GT interrupt skip the *unconditional*
> checking of the display pipes.
> 
> This gives a 20% improvement in *walltime* of GEM execution tests on my
> Braswell nuc.

Ignoring the fact that this patch missed an interrupt and so is fubar,
10% of that walltime improvement actually came from latency reductions
elsewhere, I compared against the wrong baseline.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre