svga: Update the backing resource only if needed

This patch adds a timestamp in svga_surface structure to keep track
of when the backing surface is last sync with the original resource.
This helps to avoid unnecessary surface copy from the original
resource to the backing surface if the original resource has not
since been modified.

This reduces the amount of surface copy with CinebenchR15.

Tested with CinebenchR15, mtt glretrace.

Reviewed-by: Brian Paul <brianp@vmware.com>

diff --git a/src/gallium/drivers/svga/svga_surface.c b/src/gallium/drivers/svga/svga_surface.c
index d0dc58d10f3b0da1a43b4728e33f97612814e886..cbeaa2390cd82a569ce78306ea86f84edd89b7e7 100644 (file)
--- a/src/gallium/drivers/svga/svga_surface.c
+++ b/src/gallium/drivers/svga/svga_surface.c
@@ -416,10 +416,11 @@ create_backed_surface_view(struct svga_context *svga, struct svga_surface *s)
 
       s->backed = svga_surface(backed_view);
    }
-   else {
+   else if (s->backed->age < tex->age) {
       /*
        * There is already an existing backing surface, but we still need to
-       * sync the handles.
+       * sync the backing resource if the original resource has been modified
+       * since the last copy.
        */
       struct svga_surface *bs = s->backed;
       unsigned int layer, zslice;
@@ -445,6 +446,7 @@ create_backed_surface_view(struct svga_context *svga, struct svga_surface *s)
    }
 
    svga_mark_surface_dirty(&s->backed->base);
+   s->backed->age = tex->age;
 
    SVGA_STATS_TIME_POP(svga_sws(svga));
 
@@ -647,8 +649,11 @@ svga_mark_surface_dirty(struct pipe_surface *surf)
 
    /* Increment the view_age and texture age for this surface's mipmap
     * level so that any sampler views into the texture are re-validated too.
+    * Note: we age the texture for backed surface view only when the
+    *       backed surface is propagated to the original surface.
     */
-   svga_age_texture_view(tex, surf->u.tex.level);
+   if (s->handle == tex->handle)
+      svga_age_texture_view(tex, surf->u.tex.level);
 }
 
 
@@ -742,6 +747,9 @@ svga_propagate_surface(struct svga_context *svga, struct pipe_surface *surf,
                                   1);
          svga_define_texture_level(tex, layer + i, surf->u.tex.level);
       }
+
+      /* Sync the surface view age with the texture age */
+      s->age = tex->age;
    }
 
    SVGA_STATS_TIME_POP(ss->sws);

diff --git a/src/gallium/drivers/svga/svga_surface.h b/src/gallium/drivers/svga/svga_surface.h
index 7cbb7671de40979ad668bd6e64f807d34e1093f3..d1628d54525bc90d6f395ccbab98d436ea66a096 100644 (file)
--- a/src/gallium/drivers/svga/svga_surface.h
+++ b/src/gallium/drivers/svga/svga_surface.h
@@ -72,6 +72,9 @@ struct svga_surface
     * original surface is the shader resource.
     */
    struct svga_surface *backed;
+   unsigned age;                   /* timestamp when the backed resource is
+                                    * synced with the original resource.
+                                    */
 };