From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx> Reduced re-spin of my previous series after Christian corrected a few misconceptions that I had. So lets see if what remains makes sense or is still misguided. To summarise, the series address the following two issues: * Migration rate limiting does not work, at least not for the common case where userspace configures VRAM+GTT. It thinks it can stop migration attempts by playing with bo->allowed_domains vs bo->preferred domains but, both from the code, and from empirical experiments, I see that not working at all. When both masks are identical fiddling with them achieves nothing. Even when they are not identical allowed has a fallback GTT placement which means that when over the migration budget ttm_bo_validate with bo->allowed_domains can cause migration from GTT to VRAM. * Driver thinks it will be re-validating evicted buffers on the next submission but it does not for the very common case of VRAM+GTT because it only checks if current placement is *none* of the preferred placements. These two patches appear to have a positive result for a memory intensive game like Assassin's Creed Valhalla. On an APU like Steam Deck the game has a working set around 5 GiB, while the VRAM is configured to 1 GiB. Correctly respecting the migration budget appears to keep buffer blits at bay and improves the minimum frame rate, ie. makes things smoother. >From the game's built-in benchmark, average of three runs each: FPS migrated KiB min avg max min-1% min-0.1% because 20784781 10.00 37.00 89.67 22.00 12.33 patched 4227688 13.67 37.00 81.33 23.33 15.00 Disclaimers that I have is that more runs would be needed to be more confident about the results. And more games. And APU versus discrete. Cc: Christian König <christian.koenig@xxxxxxx> Cc: Friedrich Vock <friedrich.vock@xxxxxx> Tvrtko Ursulin (2): drm/amdgpu: Re-validate evicted buffers drm/amdgpu: Actually respect buffer migration budget drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 112 +++++++++++++++++++------ drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 21 ++++- 2 files changed, 103 insertions(+), 30 deletions(-) -- 2.44.0
