Re: Snappy GUI response

On Tue, Jul 08, 2003 at 07:53:23AM -0400, Alan Cox wrote:
> > That said, getting images from the chip, even if doing it with DMA is an
> > expensive operation. Nowaday, most graphic cards have programmable
> 
> Not that expensive. You get the full DMA/AGP bandwidth streaming by DMA
> you get a tiny fraction of it otherwise

Ah, but you have to sync the graphic pipeline to make sure that anything
you did draw did also make it to the framebuffer, to be able to read it
back. Sure, i guess this is not as important for 2D as it is for 3D, but
it is still something you have to think about. While if you do
everything (and i say everything, since if you mix SW and HW access you
have to sync too) in HW, you just need to send the data and commands to
the chip, without ever bothering to read anything back.

But then, altough it is a round trip from the server to the graphic
hardware, i guess it is much less expensive than the client/server
round-trip.

Friendly,

Sven Luther