I was experimenting the new CFS v8/v9 process scheduler
on Linux and tried to start multiple glxgears
to see whether they are really running smooth and
have evenly distributed framerate.

At first I could only start two instances of glxgears
but the third didn't start saying that it cannot allocate
GART memory and try to increase increase GARTSize.

First problem: man radeon doesn't have anything about
this option, although radeon_drv.so contains this keyword.
I tried guessing whether the parameter is in MBs and
have set it to 128 but it disabled DRI because of some
out of memory condition. Setting it to 64 gave me working
DRI and I am able to start up some more instances of
glxgears.

Second problem: if I start 16 of them, the last 3
behaves very strange, i.e. instead of the spinning gears
I get chaotic flickering triangles. As soon as the number
of glxgears goes down to 13 every window behaves
normal.

Third problem: starting up 32 glxgears locked up the
machine almost instantly but having only 16 of them
also locks up the machine after some time passed.

The machine is x86-64, Athlon64 X2 4200,
PCIe Radeon X700 with 128MB onboard memory,
up-to-date Fedora Core 6. Software versions:

$ rpm -q libdrm xorg-x11-server-Xorg xorg-x11-drv-ati mesa-libGL
libdrm-2.3.0-1.fc6
libdrm-2.3.0-1.fc6
xorg-x11-server-Xorg-1.1.1-47.8.fc6
xorg-x11-drv-ati-6.6.3-1.fc6
mesa-libGL-6.5.1-9.fc6
mesa-libGL-6.5.1-9.fc6