radeonsi: tweak clear/copy_buffer limits when to use compute

Acked-by: Pierre-Eric Pelloux-Prayer <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4935>

1 files changed, 43 insertions, 6 deletions

diff --git a/src/gallium/drivers/radeonsi/si_compute_blit.c b/src/gallium/drivers/radeonsi/si_compute_blit.c
index 97ca936f810..ce19c428f1c 100644
--- a/src/gallium/drivers/radeonsi/si_compute_blit.c
+++ b/src/gallium/drivers/radeonsi/si_compute_blit.c
@@ -327,12 +327,31 @@ void si_clear_buffer(struct si_context *sctx, struct pipe_resource *dst, uint64_
 
    uint64_t aligned_size = size & ~3ull;
    if (aligned_size >= 4) {
-      /* Before GFX9, CP DMA was very slow when clearing GTT, so never
-       * use CP DMA clears on those chips, because we can't be certain
-       * about buffer placements.
+      uint64_t compute_min_size;
+
+      /* CP DMA clears are terribly slow with GTT on GFX6-8, which can always
+       * happen due to BO evictions.
        */
+      if (sctx->chip_class <= GFX8) {
+         compute_min_size = 0;
+      } else if (sctx->chip_class >= GFX10 &&
+                 sctx->screen->info.has_dedicated_vram &&
+                 si_resource(dst)->domains & RADEON_DOMAIN_VRAM) {
+         /* VRAM clears on gfx10 dGPUs */
+         if (sctx->screen->info.vram_bit_width >= 192)
+            compute_min_size = 128 * 1024;
+         else
+            compute_min_size = 1024 * 1024;
+      } else if (sctx->screen->info.has_dedicated_vram &&
+                 si_resource(dst)->domains & RADEON_DOMAIN_GTT) {
+         /* GTT clears on gfx9 and gfx10 dGPUs */
+         compute_min_size = UINT64_MAX; /* CP DMA is the best due to slow PCIe */
+      } else {
+         compute_min_size = 32 * 1024;
+      }
+
       if (clear_value_size > 4 || (!force_cpdma && clear_value_size == 4 && offset % 4 == 0 &&
-                                   (size > 32 * 1024 || sctx->chip_class <= GFX8))) {
+                                   size > compute_min_size)) {
          si_compute_do_clear_or_copy(sctx, dst, offset, NULL, 0, aligned_size, clear_value,
                                      clear_value_size, coher);
       } else {
@@ -371,11 +390,29 @@ void si_copy_buffer(struct si_context *sctx, struct pipe_resource *dst, struct p
 
    enum si_coherency coher = SI_COHERENCY_SHADER;
    enum si_cache_policy cache_policy = get_cache_policy(sctx, coher, size);
+   uint64_t compute_min_size;
+
+   if (sctx->chip_class >= GFX10 &&
+       sctx->screen->info.has_dedicated_vram &&
+       si_resource(dst)->domains & RADEON_DOMAIN_VRAM &&
+       si_resource(src)->domains & RADEON_DOMAIN_VRAM) {
+      /* VRAM copies on gfx10 dGPUs */
+      if (sctx->screen->info.vram_bit_width >= 192)
+         compute_min_size = 128 * 1024;
+      else
+         compute_min_size = 1024 * 1024;
+   } else if (sctx->chip_class >= GFX10 &&
+              sctx->screen->info.has_dedicated_vram &&
+              (si_resource(dst)->domains | si_resource(src)->domains) & RADEON_DOMAIN_GTT) {
+      compute_min_size = UINT64_MAX; /* CP DMA is the best due to slow PCIe */
+   } else {
+      compute_min_size = 32 * 1024;
+   }
 
    /* Only use compute for VRAM copies on dGPUs. */
    if (sctx->screen->info.has_dedicated_vram && si_resource(dst)->domains & RADEON_DOMAIN_VRAM &&
-       si_resource(src)->domains & RADEON_DOMAIN_VRAM && size > 32 * 1024 && dst_offset % 4 == 0 &&
-       src_offset % 4 == 0 && size % 4 == 0) {
+       si_resource(src)->domains & RADEON_DOMAIN_VRAM && size > compute_min_size &&
+       dst_offset % 4 == 0 && src_offset % 4 == 0 && size % 4 == 0) {
       si_compute_do_clear_or_copy(sctx, dst, dst_offset, src, src_offset, size, NULL, 0, coher);
    } else {
       si_cp_dma_copy_buffer(sctx, dst, src, dst_offset, src_offset, size, 0, coher, cache_policy);