drm/i915: Allow userspace to hint that the relocations were known
Userspace is able to hint to the kernel that its command stream and auxiliary state buffers already hold the correct presumed addresses and so the relocation process may be skipped if the kernel does not need to move any buffers in preparation for the execbuffer. Thus for the common case where the allotment of buffers is static between batches, we can avoid the overhead of individually checking the relocation entries. Note that this requires userspace to supply the domain tracking and requests for workarounds itself that would otherwise be computed based upon the relocation entries. Using copywinwin10 as an example that is dependent upon emitting a lot of relocations (2 per operation), we see improvements of: c2d/gm45: 618000.0/sec to 632000.0/sec. i3-330m: 748000.0/sec to 830000.0/sec. (measured relative to a baseline with neither optimisations applied). Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Reviewed-by: NImre Deak <imre.deak@intel.com> [danvet: Fixup merge conflict in userspace header due to different baseline trees.] Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
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