--- Paul [private mail] wrote:
> You might like to do some performance measurements on
> X with a shadow framebuffer - see
>
> http://www.xfree86.org/4.1.0/apm5.html
This seems to still use the processor to copy the shadow buffer
to the video memory, you will still have the PCI write stall...
> I have a machine with an SiS 630 where the video memory _is_
> main memory - the impact of the graphics processor continually
> DMAing data for display is huge.
I am not speaking of DMA'ing at the refresh frequency (approx 70 times
per second the complete video memory), just the modified 64Kb blocks,
"once upon a while": if a single pixel is written twice, you will just
see the latter written value on the screen - but who cares.
Been able to DMA the complete video memory image around 5-10 times/second
should be over the human eye sensitivity.
Moreover this pixel will stay on the processor memory cache a lot
longer, even without MTRR processors.
Etienne.
___________________________________________________________
Do You Yahoo!? -- Un e-mail gratuit @yahoo.fr !
Yahoo! Courrier : http://fr.mail.yahoo.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Oct 07 2001 - 21:00:32 EST