[PATCH] drm/amdgpu: fix ocl test performance drop

[Christian König]

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 <Flora.Cui at amd.com>

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) {
> +	if (ring->funcs->emit_vm_flush &&
> +	    (job->vm_needs_flush || amdgpu_vm_had_gpu_reset(adev, id))) {
>   		struct fence *fence;
>   
>   		trace_amdgpu_vm_flush(ring, job->vm_id, job->vm_pd_addr);