[RFC] drm/ttm: add minimum residency constraint for bo eviction

[Michel Dänzer]

On Don, 2012-11-29 at 10:18 +0100, Thomas Hellstrom wrote: 
> On 11/28/2012 10:51 PM, Marek Olšák wrote:
> > I think the problem with Radeon/TTM is much deeper. Let me demonstrate
> > it on the following example.
> >
> > Unigine Heaven needs about 385MB of space for static resources, that's
> > only 75% of my 512MB card. Yet, TTM is not capable of getting all of
> > that into VRAM. If I allow GTT placements, I get 20 fps, which is the
> > old Mesa behavior. If I force VRAM placements, I get 3 fps, because we
> > validate buffers 10 times per frame and there's probably a lot of
> > buffer evictions during each validation.
> >
> 
> Marek,
> Did you look at the total amount of referenced buffers in the ring 
> including vertex buffers?
> 
> Depending on how hard you throttle, I guess vertex / index buffer data 
> referenced by the
> ring commands may well exceed the VRAM limitation.

I think another reason 100% is not possible is fragmentation. Has anyone
ever thought about defragmentation?


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