Re: [Mesa3d-dev] radeon r200 TCL in xorg-video-ati 6.10

[martin k. <blu...@gm...>]

Thank you, Roland, for the prompt reply.

'R200_DEBUG=fall' did not reveal any sw fallbacks, so my inital
assumption of a potential TCL such occuring appears to be wrong. On
the other hand, 'R200_DEBUG=all' showed something interesting.

For a sequence of identical STATIC_DRAW-kind VBO-carried draws, of the form:


for (unsigned i = 0; i < draw_iterations; i++)
        glDrawElements(GL_TRIANGLES, num_indices, GL_UNSIGNED_SHORT, 0);


where the vertex/index buffers have been created as:



glGenBuffersARB(2, vboId);

glBindBufferARB(GL_ARRAY_BUFFER_ARB, vboId[0]);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, vert_arr_size, vert_arr,
GL_STATIC_DRAW_ARB);

glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, vboId[1]);
glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB, idx_arr_size, idx_arr,
GL_STATIC_DRAW_ARB);

glVertexPointer(3, GL_FLOAT, sizeof_vertex, offs_pos);
glNormalPointer(   GL_FLOAT, sizeof_vertex, offs_nrm);

glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);



'R200_DEBUG=all' reports that the number of r200AllocDmaRegion()
invocations scales with the value of draw_iterations from the draw
snippet.

Now, given that we are dealing with a single, supposedly static vertex
buffer here, i find this number-of-draws-proportial DMA handling quite
curious. What am i missing?

Best regards,
martin

ps: since you mentioned the possibility of potential unpotimized paths
in the DRI edge: the performance issues i've been referring to are
strictly TCL-related. In all other aspects this DRI edge performs up
to the hw specs.

On Mon, Apr 27, 2009 at 12:58 PM, Roland Scheidegger <sr...@vm...> wrote:
> I'm not aware of any problems with hw TCL or ARB_vp on any r200 chip
> (and it shouldn't matter if pci or agp for this). You can use
> R200_DEBUG=fall env var to see if the code hits any fallbacks.
> Note that there are however cases the code is not optimized for and
> might get excessively slow (like doing CopyTexImage which isn't hardware
> accelerated).
>
> Roland
>