radv: Use L2 for CP DMA on GFX9+.

This enables assuming that the L2 is always up to date for barriers.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7202>

diff --git a/src/amd/vulkan/si_cmd_buffer.c b/src/amd/vulkan/si_cmd_buffer.c
index 9763697..28d4a01 100644 (file)
--- a/src/amd/vulkan/si_cmd_buffer.c
+++ b/src/amd/vulkan/si_cmd_buffer.c
@@ -1766,10 +1766,17 @@ void si_cp_dma_buffer_copy(struct radv_cmd_buffer *cmd_buffer,
                unsigned dma_flags = 0;
                unsigned byte_count = MIN2(size, cp_dma_max_byte_count(cmd_buffer));
 
-               if (cmd_buffer->device->physical_device->rad_info.chip_class >= GFX10) {
+               if (cmd_buffer->device->physical_device->rad_info.chip_class >= GFX9) {
                        /* DMA operations via L2 are coherent and faster.
-                        * TODO: GFX7-GFX9 should also support this but it
+                        * TODO: GFX7-GFX8 should also support this but it
                         * requires tests/benchmarks.
+                        *
+                        * Also enable on GFX9 so we can use L2 at rest on GFX9+. On Raven
+                        * this didn't seem to be worse.
+                        *
+                        * Note that we only use CP DMA for sizes < RADV_BUFFER_OPS_CS_THRESHOLD,
+                        * which is 4k at the moment, so this is really unlikely to cause
+                        * significant thrashing.
                         */
                        dma_flags |= CP_DMA_USE_L2;
                }
@@ -1818,10 +1825,12 @@ void si_cp_dma_clear_buffer(struct radv_cmd_buffer *cmd_buffer, uint64_t va,
                unsigned byte_count = MIN2(size, cp_dma_max_byte_count(cmd_buffer));
                unsigned dma_flags = CP_DMA_CLEAR;
 
-               if (cmd_buffer->device->physical_device->rad_info.chip_class >= GFX10) {
+               if (cmd_buffer->device->physical_device->rad_info.chip_class >= GFX9) {
                        /* DMA operations via L2 are coherent and faster.
-                        * TODO: GFX7-GFX9 should also support this but it
+                        * TODO: GFX7-GFX8 should also support this but it
                         * requires tests/benchmarks.
+                        *
+                        * Also enable on GFX9 so we can use L2 at rest on GFX9+.
                         */
                        dma_flags |= CP_DMA_USE_L2;
                }