performance work

[Neil Graham]

On Mon, 2008-12-22 at 15:36 -0700, Jordan Crouse wrote:

> You might want to re-acquire the numbers with wireless turned off and 
> the system in a very quiet state.  If you want to be extra careful, you 
> can run the benchmarks in an empty X server (no sugar) and save the 
> results to a ramfs backed directory to avoid NAND. 


The XO Numbers were recorded from a fairly inactive state.  Wireless was
active but there shouldn't have been any traffic.  I did launch X with
just an xterm, so sugar shouldn't be in play at all.  I didn't think of
the speed of nand writes however.


>  2) The accel path requires reading from video memory (which is 
> very slow)

I'm curious as to why reads from video memory are so slow,  On standard
video cards it's slow because there is quite a division between the CPU
and the video memory,  but on the geode isn't the video memory shared in
the same SDRAM as Main memory. 

There's a separate 2 meg for DCON memory, but I was under the impression
that was just to remember the last frame.

Do I have that all wrong?