[Intel-gfx] [PATCH v2 3/6] drm/i915: Use WC copies on !llc platforms for the command parser

[Chris Wilson]

On Fri, Nov 20, 2015 at 05:05:05PM +0200, Ville Syrjälä wrote:
> On Fri, Nov 20, 2015 at 10:55:58AM +0000, Chris Wilson wrote:
> > Since we blow the TLB caches by using kmap/kunmap, we may as well go the
> > whole hog and see if declaring our destination page as WC is faster than
> > keeping it as WB and using clflush. It should be!
> 
> Is this description for another patch? I can't see any WC stuff in
> there.

No, just badly written. (Admittedly at one point I did experiment with
remapping the pages as WC and discovered that did stop_macheine()...)

drm/i915: Perform inline clflushes from the command parser

On incoherent architectures, we can avoid having to clflush the
destination shadow batch as a separate pass by inlining the call to
clflush whilst we already have the kmap_atomic() around for the page.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre