Hi,
On 16/05/2024 13:18, Tvrtko Ursulin wrote:
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
Any feedback on this series?
As described above, neither migration rate limiting or re-validation of
evicted buffers seems to work as expected currently.
Regards,
Tvrtko
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(-)
