Am Freitag, den 12.11.2010, 10:11 -0500 schrieb Younes Manton: > 2010/11/12 Christian König <deathsim...@vodafone.de>: > > What I need for both the ycrcb texture and vertex uploads is a buffer in > > system memory, where the cpu access is fast and a function to tell the > > gpu to upload this buffer to vram, so the cpu doesn't need to pump the > > data over the system bus, wait for an "in use" buffer to get idle etc. > > This is what PIPE_TRANSFER_DISCARD and PIPE_USAGE_DYNAMIC or > PIPE_USAGE_STREAM were supposed to accomplish. DYNAMIC/STREAM for > placing the texture in GPU-accessible system memory and DISCARD for > allowing the driver to allocate and return new buffers if the one's > being accessed are busy. Once upon a time they did that in nvfx, but I > don't think it's been reimplemented since Nouveau went to TTM and > gallium went to transfer objects. I already thought that this was the original intention of the flags. We should get it working again or move on to a better interface (transfer objects).
> > What I need for the surface and ycrcb intermediate textures is a buffer > > directly allocated in vram and never touched by the cpu. > > And this was the default placement for textures that were marked static. > > > So we can't just differentiate by vertex/texture buffer, but need to > > look at the usage flags of those. > > From what I recall both helped a lot, especially for large videos > where the CPU had a lot of data to generate per frame and buffers > would be busy for longer. I haven't kept up with mesa lately so I > don't know if there are new ways to deal with this, but I did run into > both problems before on nvfx and there is value in dealing with them. What I did today is optimizing the vertex generation, first I'm using quads instead of triangles now, then I moved the empty block and frame coded dct handling completely into the shaders. In the end we only need to draw one quad for a macroblock instead of eight triangles. So we now need to transmit 4*15=60 floats instead of 8*3*5=120 for a macroblock, plus we now have everything ready for doing iDCT on the buffers (ok nearly everything). Christian. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
