[Mesa-dev] r600g old design -> new design

[Michel Dänzer]

On Mit, 2010-09-29 at 11:49 +0100, Keith Whitwell wrote: 
> On Wed, 2010-09-29 at 03:35 -0700, Michel Dänzer wrote:
> > On Die, 2010-09-28 at 11:40 -0400, Jerome Glisse wrote: 
> > > 
> > > - use score for placing bo, bo placement will be recorded in bo structure and
> > > each time a state is bind bo score will be updated (bo bound as framebuffer
> > > will get their score for placing into vram increase while bo bound as small
> > > vertex buffer will endup in GTT, also anytime a bo is mapped for transfer for
> > > CPU read its score for GTT placement increase thus bo that are often updated
> > > by CPU will more likely place into GTT)
> > 
> > Beware that the EXA 'classic' scheme originally (with the 'greedy' and
> > 'smart' heuristics) used a score like that to determine whether a pixmap
> > should reside in VRAM or system memory, and it could result in quite
> > erratic / inconsistent / unreproducible behaviour when the score hovered
> > around the threshold. It could make fixing or even reproducing problems
> > harder than it is already.
> 
> Did trying some sort of hysteresis - eg. having different thresholds for
> upload vs. download help?  

There actually already is a hysteresis — I forgot about that, thanks for
reminding me. I never tried playing with the threshold values, don't
know if anyone did.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer