[Mesa-dev] [PATCH 3/3] radv: prefetch VBO descriptors at the right place

[Samuel Pitoiset]

Just after the vertex shader.

This seems to give a minor boost for, at least, Serious Sam
Fusion 2017 and Dawn of War 3. I don't see any real impacts
with The Talos Principle.

Signed-off-by: Samuel Pitoiset <samuel.pitoi...@gmail.com>
---
 src/amd/vulkan/radv_cmd_buffer.c | 16 ++++++++++++++++
 src/amd/vulkan/radv_private.h    |  5 +++++
 2 files changed, 21 insertions(+)

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index b7f101eabb..a27d380eb7 100644
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -668,6 +668,17 @@ radv_emit_prefetch_TC_L2_async(struct radv_cmd_buffer 
*cmd_buffer, uint64_t va,
                si_cp_dma_prefetch(cmd_buffer, va, size);
 }
 
+static void
+radv_emit_VBO_descriptors_prefetch(struct radv_cmd_buffer *cmd_buffer)
+{
+       if (cmd_buffer->state.vb_prefetch_dirty) {
+               radv_emit_prefetch_TC_L2_async(cmd_buffer,
+                                              cmd_buffer->state.vb_va,
+                                              cmd_buffer->state.vb_size);
+               cmd_buffer->state.vb_prefetch_dirty = false;
+       }
+}
+
 static void
 radv_emit_shader_prefetch(struct radv_cmd_buffer *cmd_buffer,
                          struct radv_shader_variant *shader)
@@ -691,6 +702,7 @@ radv_emit_prefetch(struct radv_cmd_buffer *cmd_buffer,
 {
        radv_emit_shader_prefetch(cmd_buffer,
                                  pipeline->shaders[MESA_SHADER_VERTEX]);
+       radv_emit_VBO_descriptors_prefetch(cmd_buffer);
        radv_emit_shader_prefetch(cmd_buffer,
                                  pipeline->shaders[MESA_SHADER_TESS_CTRL]);
        radv_emit_shader_prefetch(cmd_buffer,
@@ -1827,6 +1839,10 @@ radv_cmd_buffer_update_vertex_descriptors(struct 
radv_cmd_buffer *cmd_buffer, bo
 
                radv_emit_userdata_address(cmd_buffer, 
cmd_buffer->state.pipeline, MESA_SHADER_VERTEX,
                                           AC_UD_VS_VERTEX_BUFFERS, va);
+
+               cmd_buffer->state.vb_va = va;
+               cmd_buffer->state.vb_size = count * 16;
+               cmd_buffer->state.vb_prefetch_dirty = true;
        }
        cmd_buffer->state.vb_dirty = false;
 
diff --git a/src/amd/vulkan/radv_private.h b/src/amd/vulkan/radv_private.h
index 0f48681c94..83cc01ede7 100644
--- a/src/amd/vulkan/radv_private.h
+++ b/src/amd/vulkan/radv_private.h
@@ -809,7 +809,12 @@ struct radv_attachment_state {
 };
 
 struct radv_cmd_state {
+       /* Vertex descriptors */
        bool                                          vb_dirty;
+       bool                                          vb_prefetch_dirty;
+       uint64_t                                      vb_va;
+       unsigned                                      vb_size;
+
        bool                                          push_descriptors_dirty;
        bool predicating;
        radv_cmd_dirty_mask_t                         dirty;
-- 
2.15.0

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