Am 19.05.2017 um 04:25 schrieb Flora Cui:
On Thu, May 18, 2017 at 01:38:15PM +0200, Christian König wrote:
Am 18.05.2017 um 09:45 schrieb Flora Cui:
partial revert commit <6971d3d> - drm/amdgpu: cleanup logic in
amdgpu_vm_flush
Change-Id: Iadce9d613dfe9a739643a74050cea55854832adb
Signed-off-by: Flora Cui <[email protected]>
I don't see how the revert should be faster than the original.
Especially that amdgpu_vm_had_gpu_reset() is now called twice sounds like
more overhead than necessary.
Please explain further.
Christian.
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 88420dc..a96bad6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -743,23 +743,19 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct
amdgpu_job *job)
id->gws_size != job->gws_size ||
id->oa_base != job->oa_base ||
id->oa_size != job->oa_size);
- bool vm_flush_needed = job->vm_needs_flush ||
- amdgpu_vm_ring_has_compute_vm_bug(ring);
unsigned patch_offset = 0;
int r;
- if (amdgpu_vm_had_gpu_reset(adev, id)) {
- gds_switch_needed = true;
- vm_flush_needed = true;
- }
-
- if (!vm_flush_needed && !gds_switch_needed)
+ if (!job->vm_needs_flush && !gds_switch_needed &&
+ !amdgpu_vm_had_gpu_reset(adev, id) &&
+ !amdgpu_vm_ring_has_compute_vm_bug(ring))
return 0;
if (ring->funcs->init_cond_exec)
patch_offset = amdgpu_ring_init_cond_exec(ring);
- if (ring->funcs->emit_vm_flush && vm_flush_needed) {
[flora]: for compute ring & amdgpu_vm_ring_has_compute_vm_bug(), a vm_flush is
inserted. This might cause performance drop.
Ah, I see. We only need the pipeline sync, but not the vm flush.
In this case I suggest to just change the following line in
amdgpu_vm_flush():
- bool vm_flush_needed = job->vm_needs_flush ||
- amdgpu_vm_ring_has_compute_vm_bug(ring);
We can keep it in amdgpu_vm_need_pipeline_sync().
BTW: We should cache the result of amdgpu_vm_ring_has_compute_vm_bug()
in the vm manager structure. Computing this on the fly for every command
submissions is just a huge bunch of overhead.
Regards,
Christian.
_______________________________________________
amd-gfx mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
