i965: Use BDW_MOCS_PTE for renderbuffers.
Write-back caching cannot be used for buffers being scanned out by the
display engine; surfaces used for scan-out must be write-through or
uncached. I originally chose WT for render targets because it works in
all cases. However, we really want to use write-back caching where
possible, as it is more efficient.
Most renderbuffers are not used for scanout - off-screen FBOs certainly
are fine, and non-pageflipped backbuffers should be fine as well. So
in most cases WB will work. However, we don't know what will be used
for scan-out, so we instead simply use the PTE value specified by the
kernel, as it knows these things.
This matches our MOCS choice on Haswell.
Fixes performance regressions since commit ee4484be3d
in a microbenchmark (spotted by Eero Tamminen). Improves performance
in GLBenchmark 2.7/EgyptHD by 7.44362% +/- 0.496939% (n=55) on a
Broadwell GT2. Improves performance in a bunch of other microbenchmarks
by ~15% or so.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reported-by: Eero Tamminen <eero.t.tamminen@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>
Cc: mesa-stable@lists.freedesktop.org
This commit is contained in:
parent
d489a8a73d
commit
b7844d1248
|
@ -377,7 +377,7 @@ gen8_update_renderbuffer_surface(struct brw_context *brw,
|
|||
horizontal_alignment(mt) |
|
||||
surface_tiling_mode(tiling);
|
||||
|
||||
surf[1] = SET_FIELD(BDW_MOCS_WT, GEN8_SURFACE_MOCS) | mt->qpitch >> 2;
|
||||
surf[1] = SET_FIELD(BDW_MOCS_PTE, GEN8_SURFACE_MOCS) | mt->qpitch >> 2;
|
||||
|
||||
surf[2] = SET_FIELD(width - 1, GEN7_SURFACE_WIDTH) |
|
||||
SET_FIELD(height - 1, GEN7_SURFACE_HEIGHT);
|
||||
|
|
Loading…
Reference in New Issue