[Intel-gfx] [intel-gfx][PATCH] intel: add a new interface drm_intel_bo_alloc_direct

[Xiang, Haihao]

On Thu, 2010-05-27 at 04:52 +0800, Eric Anholt wrote: 
> On Tue, 25 May 2010 13:06:50 +0800, "Xiang, Haihao" <haihao.xiang at intel.com> wrote:
> > This interface is the same as drm_intel_bo_alloc except the allocated
> > size isn't rounded up, so it bypasses the cache bucket.
> > 
> > The size of the BO created by drm_intel_bo_alloc for a 1920x800,4:2:0 YUV
> > planar surface is 4M, it is about 2.2M if using drm_intel_bo_alloc_direct.
> 
> You could just init a cache bucket of that size, and get BO caching with
> no overhead and no new interfaces.

I ever considered modifying the cache bucket, including a new interface
to override the default cache bucket. The problem is that the the size
of the surface BO and related BO may vary from case to case, we don't
know the right size when initializing cache bucket.

Caching BO can improve performance, user may cache those BOs by itself. 

H.264 supports up to 16 reference frames, my testing shows that the new
interface can reduce graphics memory footprint. It can help us to
support dual HD video playback.

Thanks
Haihao