Performance change from X in Fedora Core 4 to Fedora Core 5

[Carsten Haitzler (The Rasterman)]

On Wed, 12 Jul 2006 16:13:17 +0100 Felix Bellaby <felix at bellaby.plus.com>
babbled:

> On Wed, 2006-07-12 at 14:31 +0200, Clemens Eisserer wrote:
> > > The GPU will be
> > > unable to use pipelines effectively on drawables that are created and
> > > destroyed rapidly.
> > 
> > Where do you know this from? At least nvidia developers say exactly
> > the opposite.
> 
> I must confess that it was a guess on my part. If nvidia have confided
> otherwise then bully for them. I wonder how they do it, and whether it
> is as fast as drawing to a stable drawable? 

it is give and take. you incur some extra expense for a temporary pixmap
allocation and de-allocation in return for not holding on to that video ram
permanently and thus eventually running out of video ram and needing to swap
things in and out of video ram and possibly force your os to start swapping
to/from disk. chances that you need all of that tmp pixmap space (the worst
case scenario is a whole window in size per window for all windows) all at the
same time for redrawing is very unlikely. so it is again a trade-off. i would
much sooner save the video ram as it is so incredibly easy to fill it up and
run out this way and then watch performance drop through the floor, that you
want to save the ram, if you can. the allocation expense, in my experience with
a range of x drivers and cards over a decade or so of writing x code that loves
to do this kind of stuff, is very minimal to the point of "don't worry about
it".

-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    raster at rasterman.com
裸好多
Tokyo, Japan (東京 日本)