gallium: bypass u_vbuf if it's not needed (no fallbacks and no user VBOs)

This decreases CPU overhead, because u_vbuf is completely bypassed
in those cases.

Acked-by: Alyssa Rosenzweig <[email protected]>

2 files changed, 83 insertions, 7 deletions

diff --git a/src/gallium/auxiliary/cso_cache/cso_context.c b/src/gallium/auxiliary/cso_cache/cso_context.c
index 3d730ab9404..d7c017a91f2 100644
--- a/src/gallium/auxiliary/cso_cache/cso_context.c
+++ b/src/gallium/auxiliary/cso_cache/cso_context.c
@@ -64,7 +64,10 @@ struct sampler_info
 struct cso_context {
    struct pipe_context *pipe;
    struct cso_cache *cache;
+
    struct u_vbuf *vbuf;
+   struct u_vbuf *vbuf_current;
+   bool always_use_vbuf;
 
    boolean has_geometry_shader;
    boolean has_tessellation;
@@ -296,6 +299,8 @@ static void cso_init_vbuf(struct cso_context *cso, unsigned flags)
        (uses_user_vertex_buffers &&
         caps.fallback_only_for_user_vbuffers)) {
       cso->vbuf = u_vbuf_create(cso->pipe, &caps);
+      cso->vbuf_current = cso->vbuf;
+      cso->always_use_vbuf = caps.fallback_always;
    }
 }
 
@@ -1112,7 +1117,7 @@ cso_set_vertex_elements(struct cso_context *ctx,
                         unsigned count,
                         const struct pipe_vertex_element *states)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (vbuf) {
       u_vbuf_set_vertex_elements(vbuf, count, states);
@@ -1126,7 +1131,7 @@ cso_set_vertex_elements(struct cso_context *ctx,
 static void
 cso_save_vertex_elements(struct cso_context *ctx)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (vbuf) {
       u_vbuf_save_vertex_elements(vbuf);
@@ -1140,7 +1145,7 @@ cso_save_vertex_elements(struct cso_context *ctx)
 static void
 cso_restore_vertex_elements(struct cso_context *ctx)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (vbuf) {
       u_vbuf_restore_vertex_elements(vbuf);
@@ -1181,7 +1186,7 @@ void cso_set_vertex_buffers(struct cso_context *ctx,
                             unsigned start_slot, unsigned count,
                             const struct pipe_vertex_buffer *buffers)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (!count)
       return;
@@ -1197,7 +1202,7 @@ void cso_set_vertex_buffers(struct cso_context *ctx,
 static void
 cso_save_vertex_buffer0(struct cso_context *ctx)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (vbuf) {
       u_vbuf_save_vertex_buffer0(vbuf);
@@ -1211,7 +1216,7 @@ cso_save_vertex_buffer0(struct cso_context *ctx)
 static void
 cso_restore_vertex_buffer0(struct cso_context *ctx)
 {
-   struct u_vbuf *vbuf = ctx->vbuf;
+   struct u_vbuf *vbuf = ctx->vbuf_current;
 
    if (vbuf) {
       u_vbuf_restore_vertex_buffer0(vbuf);
@@ -1222,6 +1227,68 @@ cso_restore_vertex_buffer0(struct cso_context *ctx)
    pipe_vertex_buffer_unreference(&ctx->vertex_buffer0_saved);
 }
 
+/**
+ * Set vertex buffers and vertex elements. Skip u_vbuf if it's only needed
+ * for user vertex buffers and user vertex buffers are not set by this call.
+ * u_vbuf will be disabled. To re-enable u_vbuf, call this function again.
+ *
+ * Skipping u_vbuf decreases CPU overhead for draw calls that don't need it,
+ * such as VBOs, glBegin/End, and display lists.
+ *
+ * Internal operations that do "save states, draw, restore states" shouldn't
+ * use this, because the states are only saved in either cso_context or
+ * u_vbuf, not both.
+ */
+void
+cso_set_vertex_buffers_and_elements(struct cso_context *ctx,
+                                    unsigned velem_count,
+                                    const struct pipe_vertex_element *velems,
+                                    unsigned vb_count,
+                                    unsigned unbind_trailing_vb_count,
+                                    const struct pipe_vertex_buffer *vbuffers,
+                                    bool uses_user_vertex_buffers)
+{
+   struct u_vbuf *vbuf = ctx->vbuf;
+
+   if (vbuf && (ctx->always_use_vbuf || uses_user_vertex_buffers)) {
+      if (!ctx->vbuf_current) {
+         /* Unbind all buffers in cso_context, because we'll use u_vbuf. */
+         unsigned unbind_vb_count = vb_count + unbind_trailing_vb_count;
+         if (unbind_vb_count)
+            cso_set_vertex_buffers_direct(ctx, 0, unbind_vb_count, NULL);
+
+         /* Unset this to make sure the CSO is re-bound on the next use. */
+         ctx->velements = NULL;
+         ctx->vbuf_current = vbuf;
+      } else if (unbind_trailing_vb_count) {
+         u_vbuf_set_vertex_buffers(vbuf, vb_count, unbind_trailing_vb_count,
+                                   NULL);
+      }
+
+      if (vb_count)
+         u_vbuf_set_vertex_buffers(vbuf, 0, vb_count, vbuffers);
+      u_vbuf_set_vertex_elements(vbuf, velem_count, velems);
+      return;
+   }
+
+   if (ctx->vbuf_current) {
+      /* Unbind all buffers in u_vbuf, because we'll use cso_context. */
+      unsigned unbind_vb_count = vb_count + unbind_trailing_vb_count;
+      if (unbind_vb_count)
+         u_vbuf_set_vertex_buffers(vbuf, 0, unbind_vb_count, NULL);
+
+      /* Unset this to make sure the CSO is re-bound on the next use. */
+      u_vbuf_unset_vertex_elements(vbuf);
+      ctx->vbuf_current = NULL;
+   } else if (unbind_trailing_vb_count) {
+      cso_set_vertex_buffers_direct(ctx, vb_count, unbind_trailing_vb_count,
+                                    NULL);
+   }
+
+   if (vb_count)
+      cso_set_vertex_buffers_direct(ctx, 0, vb_count, vbuffers);
+   cso_set_vertex_elements_direct(ctx, velem_count, velems);
+}
 
 void
 cso_single_sampler(struct cso_context *ctx, enum pipe_shader_type shader_stage,
@@ -1717,7 +1784,7 @@ void
 cso_draw_vbo(struct cso_context *cso,
              const struct pipe_draw_info *info)
 {
-   struct u_vbuf *vbuf = cso->vbuf;
+   struct u_vbuf *vbuf = cso->vbuf_current;
 
    /* We can't have both indirect drawing and SO-vertex-count drawing */
    assert(info->indirect == NULL || info->count_from_stream_output == NULL);
diff --git a/src/gallium/auxiliary/cso_cache/cso_context.h b/src/gallium/auxiliary/cso_cache/cso_context.h
index de8c60fd2c1..0204ace34b7 100644
--- a/src/gallium/auxiliary/cso_cache/cso_context.h
+++ b/src/gallium/auxiliary/cso_cache/cso_context.h
@@ -219,6 +219,15 @@ void cso_save_constant_buffer_slot0(struct cso_context *cso,
 void cso_restore_constant_buffer_slot0(struct cso_context *cso,
                                        enum pipe_shader_type shader_stage);
 
+/* Optimized version. */
+void
+cso_set_vertex_buffers_and_elements(struct cso_context *ctx,
+                                    unsigned velem_count,
+                                    const struct pipe_vertex_element *velems,
+                                    unsigned vb_count,
+                                    unsigned unbind_trailing_vb_count,
+                                    const struct pipe_vertex_buffer *vbuffers,
+                                    bool uses_user_vertex_buffers);
 
 /* drawing */