[Mesa-dev] [PATCH] anv: Allow PMA optimization to enabled in secondary command buffers

[Lionel Landwerlin]

This makes sense to me, it would be good to have Jason's opinion.
I have a suggestion below.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

Thanks!

On 05/01/18 11:20, Alex Smith wrote:
> This was never enabled in secondary buffers because hiz_enabled was
> never set to true for those.
>
> If the app provides a framebuffer in the inheritance info when beginning
> a secondary buffer, we can determine if HiZ is enabled and therefore
> allow the PMA optimization to be enabled within the command buffer.
>
> This improves performance by ~13% on an internal benchmark on Skylake.
>
> Signed-off-by: Alex Smith <asmith at feralinteractive.com>
> ---
>   src/intel/vulkan/genX_cmd_buffer.c | 22 +++++++++++++++++++++-
>   1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/src/intel/vulkan/genX_cmd_buffer.c b/src/intel/vulkan/genX_cmd_buffer.c
> index 0bd3874db7..2036151249 100644
> --- a/src/intel/vulkan/genX_cmd_buffer.c
> +++ b/src/intel/vulkan/genX_cmd_buffer.c
> @@ -977,11 +977,31 @@ genX(BeginCommandBuffer)(
>            anv_render_pass_from_handle(pBeginInfo->pInheritanceInfo->renderPass);
>         cmd_buffer->state.subpass =
>            &cmd_buffer->state.pass->subpasses[pBeginInfo->pInheritanceInfo->subpass];
> -      cmd_buffer->state.framebuffer = NULL;
> +
> +      /* This is optional in the inheritance info. */
> +      cmd_buffer->state.framebuffer =
> +         anv_framebuffer_from_handle(pBeginInfo->pInheritanceInfo->framebuffer);
>   
>         result = genX(cmd_buffer_setup_attachments)(cmd_buffer,
>                                                     cmd_buffer->state.pass, NULL);
>   
> +      /* Record that HiZ is enabled if we can. */
> +      if (cmd_buffer->state.framebuffer) {

You might be able to knock a few lines below by reusing 
anv_cmd_buffer_get_depth_stencil_view().

> +         const VkAttachmentReference * const ds =
> +            &cmd_buffer->state.subpass->depth_stencil_attachment;
> +
> +         if (ds->attachment != VK_ATTACHMENT_UNUSED) {
> +            const struct anv_image_view * const iview =
> +               cmd_buffer->state.framebuffer->attachments[ds->attachment];
> +            const struct anv_image * const image = iview->image;
> +            enum isl_aux_usage aux_usage =
> +               anv_layout_to_aux_usage(&cmd_buffer->device->info, image,
> +                                       VK_IMAGE_ASPECT_DEPTH_BIT, ds->layout);
> +
> +            cmd_buffer->state.hiz_enabled = aux_usage == ISL_AUX_USAGE_HIZ;
> +         }
> +      }
> +
>         cmd_buffer->state.dirty |= ANV_CMD_DIRTY_RENDER_TARGETS;
>      }
>