st/mesa: optimize constant buffer uploads

The overhead of resource_create, transfer_inline_write, and resource_destroy
to upload constant data is very visible with some apps in sysprof, and
as such should be eliminated.

My approach uses a user buffer to pass a pointer to a driver. This gives
the driver the freedom it needs to take the fast path, which may differ
for each driver.

This commit addresses the same issue as Jakob's one that suballocates out
of a big constant buffer, but it also eliminates the copy to the buffer.

1 files changed, 0 insertions, 7 deletions

diff --git a/src/mesa/state_tracker/st_context.c b/src/mesa/state_tracker/st_context.c
index 21bb91f47a8..c7f3949bf9e 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -207,12 +207,6 @@ static void st_destroy_context_priv( struct st_context *st )
       pipe_sampler_view_reference(&st->state.sampler_views[i], NULL);
    }
 
-   for (i = 0; i < Elements(st->state.constants); i++) {
-      if (st->state.constants[i]) {
-         pipe_resource_reference(&st->state.constants[i], NULL);
-      }
-   }
-
    if (st->default_texture) {
       st->ctx->Driver.DeleteTexture(st->ctx, st->default_texture);
       st->default_texture = NULL;
@@ -245,7 +239,6 @@ void st_destroy_context( struct st_context *st )
 
    for (i = 0; i < PIPE_SHADER_TYPES; i++) {
       pipe->set_constant_buffer(pipe, i, 0, NULL);
-      pipe_resource_reference(&st->state.constants[i], NULL);
    }
 
    _mesa_delete_program_cache(st->ctx, st->pixel_xfer.cache);