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author | Kenneth Graunke <[email protected]> | 2014-09-30 01:15:56 -0700 |
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committer | Kenneth Graunke <[email protected]> | 2014-10-09 15:03:32 +0200 |
commit | b7844d12487dbac702ecd734faeffa6fe1a61a83 (patch) | |
tree | dc2834132baac6958373a07af0771d1e4b5b26b0 /doxygen | |
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 <[email protected]>
Reported-by: Eero Tamminen <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Reviewed-by: Kristian Høgsberg <[email protected]>
Cc: [email protected]
Diffstat (limited to 'doxygen')
0 files changed, 0 insertions, 0 deletions