[MPlayer-dev-eng] DMA or not DMA

[Arpi]

Hi,

> > p4 is fully loaded by playing 4 streams over mga_vid.
> > (agp mga_vid was 17% cpu usg, pci ones eat 25% each)
> > using fbdev in 32bpp, only 2 playbacks possible, at 16bpp only 3.
> > the decoding was only 9% cpu per stream, the rest was eaten up by
> > video data transfers. so dma could help here a lot.

> maybe you're using the wrong kind of machine...
> you should try a bi-opteron box instead of that lowly P4 machine. it 
> should be fast enough for just about anything...
> the problem here is not the P4 but that the processor to northbridge 
> bandwith is maxed out. in effect, the same link is used to connect the 
> processor to the memory and the PCI/AGP busses.
> 
> remember, the pci bus on a machine can only do 1056Mbit/s, and a 
> noncompressed 8 bit 4.2.2 video is about 165Mbit/s
> 
> if you use a dual opteron box, you'll have tons more bandwith available 
> to the pci/pci-X busses and it should work without a problem.

a dual opteron will
- cost lots of money
- will have heating problems (when running 24/7 for weeks in a small closed
room or box)

even the 3ghz p4 is over our target, i hoped that an 1ghz p3 or 2ghz p4
will eb far enough, knowing that 250mgh p2 could decode and display one
such stream with a g400 with no problem.


A'rpi / MPlayer, Astral & ESP-team

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