Technical stuff for game programmers, but interesting because it
shows why good Linux 3D animated games must directly bypass most of
the OS.
“… if your driver is communicating over any standard
communication pipe (like X), you are pretty much SOL. The data
traffic is so high that a good framerate is going to be almost
impossible to achieve. A direct rendering model is needed to get
reasonable performance.
“Next, if your driver is directly writing to a small command
FIFO on the chip, you will be limited to about 2/3 or less of the
framerate you could get with a fully decoupled DMA buffer approach.
It is possible to get a playable game with a directly writing
driver, but it won?t be running with the best of them…”