tree 983e005a68677353a716755ade1a83f3593cba19
parent a8aab8bd5efe1377ea2b0d2b51b26989eea6906d
author Chris Wilson <chris@chris-wilson.co.uk> 1402398880 +0100
committer Daniel Vetter <daniel.vetter@ffwll.ch> 1402665461 +0200

drm/i915: Prefault the entire object on first page fault

Inserting additional PTEs has no side-effect for us as the pfn are fixed
for the entire time the object is resident in the global GTT. The
downside is that we pay the entire cost of faulting the object upon the
first hit, for which we in return receive the benefit of removing the
per-page faulting overhead.

On an Ivybridge i7-3720qm with 1600MHz DDR3, with 32 fences,
Upload rate for 2 linear surfaces:	8127MiB/s -> 8134MiB/s
Upload rate for 2 tiled surfaces:	8607MiB/s -> 8625MiB/s
Upload rate for 4 linear surfaces:	8127MiB/s -> 8127MiB/s
Upload rate for 4 tiled surfaces:	8611MiB/s -> 8602MiB/s
Upload rate for 8 linear surfaces:	8114MiB/s -> 8124MiB/s
Upload rate for 8 tiled surfaces:	8601MiB/s -> 8603MiB/s
Upload rate for 16 linear surfaces:	8110MiB/s -> 8123MiB/s
Upload rate for 16 tiled surfaces:	8595MiB/s -> 8606MiB/s
Upload rate for 32 linear surfaces:	8104MiB/s -> 8121MiB/s
Upload rate for 32 tiled surfaces:	8589MiB/s -> 8605MiB/s
Upload rate for 64 linear surfaces:	8107MiB/s -> 8121MiB/s
Upload rate for 64 tiled surfaces:	2013MiB/s -> 3017MiB/s

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "Goel, Akash" <akash.goel@intel.com>
Testcasee: igt/gem_fence_upload/performance
Reviewed-by: Brad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>