[Mesa-dev] [PATCH 20/29] anv/cmd_buffer: Decide whether or not to HiZ clear up-front

[Pohjolainen, Topi]

On Mon, Nov 27, 2017 at 07:06:10PM -0800, Jason Ekstrand wrote:
> This moves the decision out of begin_subpass and into BeginRenderPass
> like the decision for color clears.  We use a similar name for the
> function for depth/stencil as for color even though no aux usage is
> really getting computed.
> ---
>  src/intel/vulkan/genX_cmd_buffer.c | 84 +++++++++++++++++++++++---------------
>  1 file changed, 50 insertions(+), 34 deletions(-)
> 
> diff --git a/src/intel/vulkan/genX_cmd_buffer.c b/src/intel/vulkan/genX_cmd_buffer.c
> index 57685bd..3f90c1a 100644
> --- a/src/intel/vulkan/genX_cmd_buffer.c
> +++ b/src/intel/vulkan/genX_cmd_buffer.c
> @@ -346,6 +346,52 @@ color_attachment_compute_aux_usage(struct anv_device * device,
>     }
>  }
>  
> +static void
> +depth_stencil_attachment_compute_aux_usage(struct anv_device *device,
> +                                           struct anv_cmd_state *cmd_state,
> +                                           uint32_t att, VkRect2D render_area)
> +{
> +   struct anv_attachment_state *att_state = &cmd_state->attachments[att];
> +   struct anv_image_view *iview = cmd_state->framebuffer->attachments[att];
> +
> +   /* These will be initialized after the first subpass transition. */
> +   att_state->aux_usage = ISL_AUX_USAGE_NONE;
> +   att_state->input_aux_usage = ISL_AUX_USAGE_NONE;
> +
> +   if (att_state->aux_usage != ISL_AUX_USAGE_HIZ) {
> +      att_state->fast_clear = false;
> +      return;
> +   } else if (!(att_state->pending_clear_aspects & VK_IMAGE_ASPECT_DEPTH_BIT)) {
> +      /* If we're just clearing stencil, we can always HiZ clear */
> +      att_state->fast_clear = true;

I need to check that I understood. This is possible because the clear doesn't
trigger for depth later on, right? If so, what does setting fast_clear
actually help?

> +      return;
> +   }
> +
> +   if (!blorp_can_hiz_clear_depth(GEN_GEN,
> +                                  iview->planes[0].isl.format,
> +                                  iview->image->samples,
> +                                  render_area.offset.x,
> +                                  render_area.offset.y,
> +                                  render_area.offset.x +
> +                                  render_area.extent.width,
> +                                  render_area.offset.y +
> +                                  render_area.extent.height)) {
> +      att_state->fast_clear = false;
> +   } else if (att_state->clear_value.depthStencil.depth != ANV_HZ_FC_VAL) {
> +      att_state->fast_clear = false;
> +   } else if (GEN_GEN == 8 &&
> +              anv_can_sample_with_hiz(&device->info, iview->image)) {
> +      /* Only gen9+ supports returning ANV_HZ_FC_VAL when sampling a
> +       * fast-cleared portion of a HiZ buffer. Testing has revealed that Gen8
> +       * only supports returning 0.0f. Gens prior to gen8 do not support this
> +       * feature at all.
> +       */
> +      att_state->fast_clear = false;
> +   } else {
> +      att_state->fast_clear = true;
> +   }
> +}
> +
>  static bool
>  need_input_attachment_state(const struct anv_render_pass_attachment *att)
>  {
> @@ -1052,12 +1098,9 @@ genX(cmd_buffer_setup_attachments)(struct anv_cmd_buffer *cmd_buffer,
>              add_image_view_relocs(cmd_buffer, iview, 0,
>                                    state->attachments[i].color);
>           } else {
> -            /* This field will be initialized after the first subpass
> -             * transition.
> -             */
> -            state->attachments[i].aux_usage = ISL_AUX_USAGE_NONE;
> -
> -            state->attachments[i].input_aux_usage = ISL_AUX_USAGE_NONE;
> +            depth_stencil_attachment_compute_aux_usage(cmd_buffer->device,
> +                                                       state, i,
> +                                                       begin->renderArea);
>           }
>  
>           if (need_input_attachment_state(&pass->attachments[i])) {
> @@ -3228,34 +3271,7 @@ cmd_buffer_begin_subpass(struct anv_cmd_buffer *cmd_buffer,
>                                 VK_IMAGE_ASPECT_STENCIL_BIT));
>  
>        if (att_state->pending_clear_aspects) {
> -         bool clear_with_hiz = att_state->aux_usage == ISL_AUX_USAGE_HIZ;
> -         if (clear_with_hiz &&
> -             (att_state->pending_clear_aspects & VK_IMAGE_ASPECT_DEPTH_BIT)) {
> -            if (!blorp_can_hiz_clear_depth(GEN_GEN,
> -                                           iview->planes[0].isl.format,
> -                                           iview->image->samples,
> -                                           render_area.offset.x,
> -                                           render_area.offset.y,
> -                                           render_area.offset.x +
> -                                           render_area.extent.width,
> -                                           render_area.offset.y +
> -                                           render_area.extent.height)) {
> -               clear_with_hiz = false;
> -            } else if (att_state->clear_value.depthStencil.depth != ANV_HZ_FC_VAL) {
> -               clear_with_hiz = false;
> -            } else if (GEN_GEN == 8 &&
> -                       anv_can_sample_with_hiz(&cmd_buffer->device->info,
> -                                               iview->image)) {
> -               /* Only gen9+ supports returning ANV_HZ_FC_VAL when sampling a
> -                * fast-cleared portion of a HiZ buffer. Testing has revealed
> -                * that Gen8 only supports returning 0.0f. Gens prior to gen8
> -                * do not support this feature at all.
> -                */
> -               clear_with_hiz = false;
> -            }
> -         }
> -
> -         if (clear_with_hiz) {
> +         if (att_state->fast_clear) {
>              /* We currently only support HiZ for single-layer images */
>              assert(iview->planes[0].isl.base_level == 0);
>              assert(iview->planes[0].isl.base_array_layer == 0);
> -- 
> 2.5.0.400.gff86faf
> 
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