XO-1.75 relative performance

[Jon Nettleton]

> Hi Jon,
>
> We are doing some forwards-planing with regards to the XO-1.75. Would
> you be able to tell us what kind of performance we can expect from the
> graphics driver that you are working on? Would it support 3D hardware
> acceleration?

Well yes and no.  The graphics hardware does support 3d acceleration,
however currently that is only supported via a binary driver.  We also
don't have all the documentation nor man power to write a 3d driver.
The nouveau team has had 3 to 4 people working full time on a driver
for almost 4 years and their driver is just getting to a stable usage
point for desktop compositing.

For a general idea of performance our 3d graphics hardware will run
Quake3 at native 1200x900 resolution with medium quality graphics at
about 30fps on average.

>
> We are considering working to get GNOME 3 running, but for that to
> work well we'll need some good graphics capabilities.

There should be a distinction between GNOME 3 and gnome-shell.
Gnome-shell is the only part of GNOME 3 that requires 3D acceleration.
 Could our hardware run gnome-shell?  Well that would take a bit of
time to figure out.  To my knowledge nobody has shown gnome-shell
running with clutter utilizing the OpenGLES backend.  Last I remember
clutter didn't support texture from pixmap capabilities with their EGL
backend, so that may still have to be implemented.  This may have
changed in the last couple of months by I have definitely not seen it
demonstrated or talked about anywhere.

The bigger concern I have with targeting a compositing window manager
is the amount of RAM that it needs.  Every window also has a
duplicated texture in memory that is used to create the composited
display.  Generally gnome-shell will use 100+MB's of RAM just to
display the desktop, and there is no way to tweak around this by using
16-bit colors as everything is an ARGB texture.  On a machine with 1GB
of RAM this isn't so bad, but that is a hefty chunk of memory for a
machine with 512MB's of memory.  Oh and that is just system RAM it
doesn't take into account the memory that is needed for the actual
graphics engine.

To sum things up.  Yes the hardware should have the capabilities to
run gnome-shell, again I say should as it is very untested.  I would
not recommend targetting it's use in any future plans unless you have
GNOME and Xorg hackers lined up to spend a good chunk of time working
on it.

-Jon