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

Keith Whitwell keithw at vmware.com
Wed Sep 29 03:49:18 PDT 2010

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?  


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