draw: Only run prepare when state, prim and opt changes

In bad applications like ipers which does a lot of draw calls with
no state changes this helps to greatly reduce time spent in prepare.
In ipers around 7% of CPU was spent in various prepare functions,
after this commit no prepare function show on the profile.

This commit also has the added benefit of now grouping all pipelined
drawing into a single draw call if the driver uses vbuf_render.

Reviewed-by: Stéphane Marchesin <[email protected]>
Tested-by: Stéphane Marchesin <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index 4ce44455084..3c0b1aa39c9 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -355,6 +355,10 @@ draw_set_vertex_elements(struct draw_context *draw,
 {
    assert(count <= PIPE_MAX_ATTRIBS);
 
+   /* We could improve this by only flushing the frontend and the fetch part
+    * of the middle. This would avoid recalculating the emit keys.*/
+   draw_do_flush( draw, DRAW_FLUSH_STATE_CHANGE );
+
    memcpy(draw->pt.vertex_element, elements, count * sizeof(elements[0]));
    draw->pt.nr_vertex_elements = count;
 }
@@ -654,6 +658,8 @@ void draw_do_flush( struct draw_context *draw, unsigned flags )
 
       draw_pipeline_flush( draw, flags );
 
+      draw_pt_flush( draw, flags );
+
       draw->flushing = FALSE;
    }
 }