X speed (was: Re: Squeak on an iPAQ)

Bert Freudenberg bert at isg.cs.uni-magdeburg.de
Fri Sep 22 15:11:51 UTC 2000


On Fri, 22 Sep 2000, Lex Spoon wrote:

> This has been begging to be written, just because it's conceptually
> cleaner.  But it's true: on a computer without much RAM or disk space,
> taking X out of the loop should make a real, observable difference!

Sure.

> It may well be faster, too.  

If you mean on a decent machine, I doubt this. I once tested XF86DGA,
which allows direct frame buffer access under X. The result was not
overwhelming, so I didn't go into it further. Actually, X might be faster
than fb because the accelareted drivers can do all sort of fast dma
blitting stuff, which you couldn't achieve with dga. Only if Squeak would
directly write into fb using FXBlt with no display bitmap it could be
faster.

> I've reported earlier, but Squeak on XWindows has had pretty slow
> screen updates whenever I've tested it.  I'm guessing my X server just
> isn't all that well optimized.

Yes, you really should get NVidia's drivers and XFree86 4. They're
probably much faster. I get ~ 770 ms for the resolution/depth in your
example. This is a PIII/600+GeForce, but AFAIK the 2D performance of all
NVidia cards is quite similar.

-- Bert






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