EXA and MigrationHeuristic

Michel Dänzer michel at tungstengraphics.com
Thu May 29 03:12:46 PDT 2008

On Thu, 2008-05-29 at 12:10 +0200, Lukas Hejtmanek wrote:
> On Thu, May 29, 2008 at 12:06:29PM +0200, Michel Dänzer wrote:
> > "greedy" is faster than "always" in some cases because it's quite
> > conservative about migrating pixmaps offscreen. Any single low level
> > operation can only be accelerated if all pixmaps involved are offscreen,
> > so this results in fewer operations being accelerated, thereby avoiding
> > migration overhead for operations that can't be accelerated for other
> > reasons.
> hmm what about shared memory graphics (such as Intel) and migration from video
> memory to system memory. I guess this kind of migration could be avoided at
> all as CPU should be equally fast with both the "video" memory and the system
> memory. Or is there any reason why to memcpy pixmaps from vram to ram in
> shared graphics case?

No, this is eliminated on the intel batchbuffer branch. The whole EXA
migration code is basically inactive there.

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

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