[Mesa-dev] [PATCH 4/4] gallium/radeon: align alignments for better buffer reuse

[Michel Dänzer]

On 08.05.2016 21:21, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> ---
>  src/gallium/winsys/amdgpu/drm/amdgpu_bo.c     | 1 +
>  src/gallium/winsys/radeon/drm/radeon_drm_bo.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> index eb28ba9..ed12f30 100644
> --- a/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> +++ b/src/gallium/winsys/amdgpu/drm/amdgpu_bo.c
> @@ -470,6 +470,7 @@ amdgpu_bo_create(struct radeon_winsys *rws,
>      * like constant/uniform buffers, can benefit from better and more reuse.
>      */
>     size = align64(size, ws->info.gart_page_size);
> +   alignment = align(alignment, ws->info.gart_page_size);
>  
>     /* Only set one usage bit each for domains and flags, or the cache manager
>      * might consider different sets of domains / flags compatible
> diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
> index b24964f..b07afe6 100644
> --- a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
> +++ b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
> @@ -732,6 +732,7 @@ radeon_winsys_bo_create(struct radeon_winsys *rws,
>       * like constant/uniform buffers, can benefit from better and more reuse.
>       */
>      size = align(size, ws->info.gart_page_size);
> +    alignment = align(alignment, ws->info.gart_page_size);
>  
>      /* Only set one usage bit each for domains and flags, or the cache manager
>       * might consider different sets of domains / flags compatible
> 

This is superfluous: ws->info.gart_page_size is the CPU page size. TTM
only tracks BOs at CPU page size granularity, so all BOs implicitly have
this alignment. For GPUVM, since we're aligning the BO size, all VM
address spaces we assign are implicitly aligned as well.


I'd say "gart_page_size" is a bit misleading in general, it's simply the
CPU page size and applies to all BOs, regardless of whether they're in
GART or not. Other than that, patches 1-3 look good to me.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer