[Mesa-dev] [PATCH 4/4] i965: Add support for GL_ARB_buffer_storage.

[Kenneth Graunke]

On 02/27/2014 02:53 PM, Eric Anholt wrote:
> It turns out we can allow COHERENT storage/mappings all the time,
> regardless of LLC vs non-LLC.  It just means never using temporary
> mappings to avoid GPU stalls,
> and on non-LLC we have to use the GTT intead
> of CPU mappings.  If we were to use CPU maps on non-LLC (which might be
> useful if apps end up using buffer_storage on PBO reads, to avoid WC read
> slowness), those would be PERSISTENT but not COHERENT, but doing that
> would require us driving the clflushes from userspace somehow.

Right, this makes sense to me.

This series is:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

> Using this in glamor, I got a 29.5361% +/- 2.74092% improvement in x11perf
> -aa10text (n=489).

> ---
>  docs/GL3.txt                                     | 2 +-
>  src/mesa/drivers/dri/i965/intel_buffer_objects.c | 9 +++++++--
>  src/mesa/drivers/dri/i965/intel_extensions.c     | 1 +
>  3 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/docs/GL3.txt b/docs/GL3.txt
> index 5261eda..45db98f 100644
> --- a/docs/GL3.txt
> +++ b/docs/GL3.txt
> @@ -170,7 +170,7 @@ GL 4.4:
>  
>    GLSL 4.4                                             not started
>    GL_MAX_VERTEX_ATTRIB_STRIDE                          not started
> -  GL_ARB_buffer_storage                                DONE (r300, r600, radeonsi)
> +  GL_ARB_buffer_storage                                DONE (i965, r300, r600, radeonsi)
>    GL_ARB_clear_texture                                 not started
>    GL_ARB_enhanced_layouts                              not started
>    GL_ARB_multi_bind                                    started (Fredrik Höglund)
> diff --git a/src/mesa/drivers/dri/i965/intel_buffer_objects.c b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> index 260308a..96dacde 100644
> --- a/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> +++ b/src/mesa/drivers/dri/i965/intel_buffer_objects.c
> @@ -401,8 +401,12 @@ intel_bufferobj_map_range(struct gl_context * ctx,
>      * doesn't require the current contents of that range, make a new
>      * BO, and we'll copy what they put in there out at unmap or
>      * FlushRange time.
> +    *
> +    * That is, unless they're looking for a persistent mapping -- we would
> +    * need to do blits in the MemoryBarrier call, and it's easier to just do a
> +    * GPU stall and do a mapping.
>      */
> -   if (!(access & GL_MAP_UNSYNCHRONIZED_BIT) &&
> +   if (!(access & (GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_PERSISTENT_BIT)) &&
>         (access & GL_MAP_INVALIDATE_RANGE_BIT) &&
>         drm_intel_bo_busy(intel_obj->buffer)) {
>        /* Ensure that the base alignment of the allocation meets the alignment
> @@ -429,7 +433,8 @@ intel_bufferobj_map_range(struct gl_context * ctx,
>  
>     if (access & GL_MAP_UNSYNCHRONIZED_BIT)
>        drm_intel_gem_bo_map_unsynchronized(intel_obj->buffer);
> -   else if (!brw->has_llc && !(access & GL_MAP_READ_BIT)) {
> +   else if (!brw->has_llc && (!(access & GL_MAP_READ_BIT) ||
> +                              (access & GL_MAP_PERSISTENT_BIT))) {
>        drm_intel_gem_bo_map_gtt(intel_obj->buffer);
>        intel_bufferobj_mark_inactive(intel_obj);
>     } else {
> diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
> index ef9aa55..860896a 100644
> --- a/src/mesa/drivers/dri/i965/intel_extensions.c
> +++ b/src/mesa/drivers/dri/i965/intel_extensions.c
> @@ -162,6 +162,7 @@ intelInitExtensions(struct gl_context *ctx)
>  
>     assert(brw->gen >= 4);
>  
> +   ctx->Extensions.ARB_buffer_storage = true;
>     ctx->Extensions.ARB_depth_buffer_float = true;
>     ctx->Extensions.ARB_depth_clamp = true;
>     ctx->Extensions.ARB_depth_texture = true;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: OpenPGP digital signature
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20140314/d045101a/attachment.pgp>