diff options
author | Kenneth Graunke <kenneth@whitecape.org> | 2014-09-30 01:15:56 -0700 |
---|---|---|
committer | Kenneth Graunke <kenneth@whitecape.org> | 2014-10-09 15:03:32 +0200 |
commit | b7844d12487dbac702ecd734faeffa6fe1a61a83 (patch) | |
tree | dc2834132baac6958373a07af0771d1e4b5b26b0 /src/mesa | |
parent | d489a8a73d273e9042b3de49085576c2acd5153a (diff) |
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 ee4484be3dc827cf15bcf109f5
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
Diffstat (limited to 'src/mesa')
-rw-r--r-- | src/mesa/drivers/dri/i965/gen8_surface_state.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/mesa/drivers/dri/i965/gen8_surface_state.c b/src/mesa/drivers/dri/i965/gen8_surface_state.c index 40eb2eab0ae..6dd343f57f4 100644 --- a/src/mesa/drivers/dri/i965/gen8_surface_state.c +++ b/src/mesa/drivers/dri/i965/gen8_surface_state.c @@ -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); |