[xorg] X3100 OpenGL incredibly slow and buggy on 2.2.0

[Richard Goedeken]

> Please read this :
> http://wiki.cchtml.com/index.php/Glxgears_is_not_a_Benchmark
> 
> Stephane

You're right, glxgears is not a comprehensive 3D acceleration benchmark, but it 
does measure some narrow window of system hardware performance.  Let's look at 
my 2 main systems for comparison:

Desktop PC:
- 64-bit Gentoo, older stable drivers
- Gigabyte GA-K8N Ultra-9 socket939 nForce4 Ultra ATX
- Athlon64 3800 x2 - 2.0GHz 1MB total cache
- Asus EN6600/TD/256M Silencer
   - GeForce 6600, 256M ram
   - 128 bit DDR2 ram 500MHz, 8.0 GB/s
   - 300MHz core, 8 pixel shaders, 3 vertex shaders
   - PCI Express x16
- 2GB PC3200 DDR 400MHz SDRAM (6.4 GB/s)

Set-top PC:
- 64-bit Fedora 8, git drivers for mesa/drm/intel
- AOpen MiniPC MP965-DR, Intel 965GM chipset
- Intel Core 2 Duo T7500 2.2GHz Socket P 4MB total cache
- X3100 graphics
   - shared system memory, total bandwidth 10.7 GB/s
   - 500MHz core, 8 unified shaders
- 2*1GB dual channel PC5300 DDR2 667MHZ SDRAM

By all measures it looks like the settop box would meet or beat the desktop one. 
  But the difference in 3D performance in favor of the desktop is large, not 
small.  Even if you write off a factor of 6 (!) times as many fps in glxgears, 
it remains that the N64 emulator I'm working on runs flawlessly with low CPU 
usage on the desktop box but bogs down on the MiniPC.  glxinfo says direct 
rendering is on.  If someone could suggest a good 3D benchmark for Linux I would 
be willing to run it for an experiment.  Something is wrong here.  Either the 
shared memory architecture really just clobbers real-world performance or else 
something is far from optimal in the software stack.

Richard