On Mon, Feb 18, 2002 at 02:04:29PM -0500, Vladimir Dergachev wrote: > > But I still don't understand why _X_ should hog the CPU: [cut] > Could it be that X is waiting for the engine to become quiscient ? So if > you scheduled a DMA transfer already it has to busy wait for the card to > finish. Which > a) creates unnecessary PCI traffic > b) wastes time.. This (wasting while waiting) is exaxtly what IMHO is causing this.
> The solution to this would be to not submit new frames faster than
> graphics card can handle them.
Actually, I reproduced it now with mplayer (sdl or xv) with only twm running.
mplayer eats 20%, X also. DMA is working. This sucks and I doubt it is sending
it faster than it should (I vaguely remember my card should be able to get 3
times 25fps dvd size at 16bpp). The tested video is 24 fps 640x480. It also
happens with smaller ones, but X eats less.
> Peter - Am I right in thinking that you have Rage128 card ?
Yes.
> Can you write a simple program to measure just how fast can you pump frames
> into overlay ?
I could but I'm lazy :-)
I really think it is what Michel (?) said in other email, that XSync is doing
busy-loop while waiting for the transfer to finish. I could rewrite it to do
usleep. I don't care really if it takes 10ms more to wait.
I'll report later.
> Vladimir Dergachev
Mit freundlichen Grüßen
Peter Surda (Shurdeek) <[EMAIL PROTECTED]>, ICQ 10236103, +436505122023
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