[Mesa-dev] [PATCH 2/2] anv: Enable MSAA compression

[Lionel Landwerlin]

On 18/02/17 00:03, Jason Ekstrand wrote:
> This just enables basic MSAA compression (no fast clears) for all
> multisampled surfaces.  This improves the framerate of the Sascha
> "multisampling" demo by 76% on my Sky Lake laptop.  Running Talos on
> medium settings with 8x MSAA, this improves the framerate in the
> benchmark by 80%.
> ---
>   src/intel/vulkan/TODO              |  2 +-
>   src/intel/vulkan/anv_blorp.c       |  3 ++-
>   src/intel/vulkan/anv_image.c       |  8 ++++++++
>   src/intel/vulkan/anv_pipeline.c    | 14 ++++++++++++++
>   src/intel/vulkan/genX_cmd_buffer.c |  5 +++++
>   5 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/src/intel/vulkan/TODO b/src/intel/vulkan/TODO
> index f8b73a1..daab39f 100644
> --- a/src/intel/vulkan/TODO
> +++ b/src/intel/vulkan/TODO
> @@ -9,7 +9,7 @@ Missing Features:
>   
>   Performance:
>    - Multi-{sampled/gen8,LOD} HiZ
> - - Compressed multisample support
> + - MSAA fast clears
>    - Pushing pieces of UBOs?
>    - Enable guardband clipping
>    - Use soft-pin to avoid relocations
> diff --git a/src/intel/vulkan/anv_blorp.c b/src/intel/vulkan/anv_blorp.c
> index 4e7078b..902d9af 100644
> --- a/src/intel/vulkan/anv_blorp.c
> +++ b/src/intel/vulkan/anv_blorp.c
> @@ -1397,7 +1397,8 @@ ccs_resolve_attachment(struct anv_cmd_buffer *cmd_buffer,
>      struct anv_attachment_state *att_state =
>         &cmd_buffer->state.attachments[att];
>   
> -   if (att_state->aux_usage == ISL_AUX_USAGE_NONE)
> +   if (att_state->aux_usage == ISL_AUX_USAGE_NONE ||
> +       att_state->aux_usage == ISL_AUX_USAGE_MCS)
>         return; /* Nothing to resolve */
>   
>      assert(att_state->aux_usage == ISL_AUX_USAGE_CCS_E ||
> diff --git a/src/intel/vulkan/anv_image.c b/src/intel/vulkan/anv_image.c
> index 7eb0f8f..cc47a50 100644
> --- a/src/intel/vulkan/anv_image.c
> +++ b/src/intel/vulkan/anv_image.c
> @@ -238,6 +238,14 @@ make_surface(const struct anv_device *dev,
>               }
>            }
>         }
> +   } else if (aspect == VK_IMAGE_ASPECT_COLOR_BIT && vk_info->samples > 1) {
> +      assert(image->aux_surface.isl.size == 0);
> +      assert(!(vk_info->usage & VK_IMAGE_USAGE_STORAGE_BIT));
> +      ok = isl_surf_get_mcs_surf(&dev->isl_dev, &anv_surf->isl,
> +                                 &image->aux_surface.isl);
> +      assert(ok);

Overall looks good to me, but I think you should drop the assert here.
Looking at the internal documentation I found a 8k width constraint at 
16x msaa (look at SURFACE_STATE's width field, only applies SKL+).
So I guess we fallback to not use the MCS in that case.

> +      add_surface(image, &image->aux_surface);
> +      image->aux_usage = ISL_AUX_USAGE_MCS;
>      }
>   
>      return VK_SUCCESS;
> diff --git a/src/intel/vulkan/anv_pipeline.c b/src/intel/vulkan/anv_pipeline.c
> index 4410103..3301679 100644
> --- a/src/intel/vulkan/anv_pipeline.c
> +++ b/src/intel/vulkan/anv_pipeline.c
> @@ -228,6 +228,20 @@ static void
>   populate_sampler_prog_key(const struct gen_device_info *devinfo,
>                             struct brw_sampler_prog_key_data *key)
>   {
> +   /* All multisampled textures are compressed. */
> +   key->compressed_multisample_layout_mask = ~0;
> +
> +   /* SkyLake added support for 16x MSAA.  With this came a new message for
> +    * reading from a 16x MSAA surface with compression.  The new message was
> +    * needed because now the MCS data is 64 bits instead of 32 or lower as is
> +    * the case for 8x, 4x, and 2x.  The key->msaa_16 bit-field controls which
> +    * message we use.  Fortunately, the 16x message works for 8x, 4x, and 2x
> +    * so we can just use it unconditionally.  This may not be quite as
> +    * efficient but it saves us from recompiling.
> +    */
> +   if (devinfo->gen >= 9)
> +      key->msaa_16 = ~0;
> +
>      /* XXX: Handle texture swizzle on HSW- */
>      for (int i = 0; i < MAX_SAMPLERS; i++) {
>         /* Assume color sampler, no swizzling. (Works for BDW+) */
> diff --git a/src/intel/vulkan/genX_cmd_buffer.c b/src/intel/vulkan/genX_cmd_buffer.c
> index 40a72f4..5d8c3ea 100644
> --- a/src/intel/vulkan/genX_cmd_buffer.c
> +++ b/src/intel/vulkan/genX_cmd_buffer.c
> @@ -222,6 +222,11 @@ color_attachment_compute_aux_usage(struct anv_device *device,
>         att_state->input_aux_usage = ISL_AUX_USAGE_NONE;
>         att_state->fast_clear = false;
>         return;
> +   } else if (iview->image->aux_usage == ISL_AUX_USAGE_MCS) {
> +      att_state->aux_usage = ISL_AUX_USAGE_MCS;
> +      att_state->input_aux_usage = ISL_AUX_USAGE_MCS;
> +      att_state->fast_clear = false;
> +      return;
>      }
>   
>      assert(iview->image->aux_surface.isl.usage & ISL_SURF_USAGE_CCS_BIT);