On 12/03/2010 12:47 PM, Jakob Bornecrantz wrote:
Hi all
I have attached two patches that should help with speed on applications that
causes a lot of constant buffers to be emitted or lot of constant state as in
the case of the second patch as it eliminates a memcpy.
The first patch just adds a offset and size argument to the set_constant_buffer
call on the context, making it possible for the state tracker sub-allocate the
buffers out a larger buffer. For ipers this is a pretty big win. Even if we did
something similar inside the drivers various locks would have to be taken
because since create buffer is a screen function.
The second patch switches from a inline write to map buffer call and points the
_mesa_load_state_parameters to it directly. For ipers this is a minor loss but
for application that has a different ratio of number of constants vs number of
times the constants changes it will probably be a win.
I don't see how this can work as-is. We need to put all the
parameters/constants into the buffer at the new offset, not just the
PROGRAM_STATE_VARs. Recall the the Mesa parameter/constant buffer
constains PROGRAM_STATE_VAR (i.e. fixed-function state) plus the
user's uniforms, program parameters, shader literals, etc.
You should test some GLSL programs too.
In _mesa_load_state_parameters_to() you might try adding an else
clause to the Type == PROGRAM_STATE_VAR conditional which copies the
current parameter value to the dest buffer.
I have tested the patches on i915g only, unfortunately I based the i915 part
of these patches on some other work I had laying around so there is no point
in sending them out since they wont apply.
Before I go and try and change the other drivers I would like to hear some input
on these changes. So comment please, anyways have a nice weekend.
[...]
diff --git a/src/mesa/state_tracker/st_context.c
b/src/mesa/state_tracker/st_context.c
index d6628b1..303b924 100644
--- a/src/mesa/state_tracker/st_context.c
+++ b/src/mesa/state_tracker/st_context.c
@@ -244,8 +244,8 @@ void st_destroy_context( struct st_context *st )
pipe->set_index_buffer(pipe, NULL);
for (i = 0; i < PIPE_SHADER_TYPES; i++) {
- pipe->set_constant_buffer(pipe, PIPE_SHADER_VERTEX, 0, NULL);
- pipe_resource_reference(&st->state.constants[PIPE_SHADER_VERTEX], NULL);
+ pipe->set_constant_buffer(pipe, i, 0, 0, 0, NULL);
+ pipe_resource_reference(&st->state.constants[i], NULL);
}
This bug fix should be committed soon in any case. Looks like it
comes from Tilman's commit 646a8b7e1dfbd126819d577a94102e64748d0b9d
-Brian
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