Re: [Dri-devel] [patch] r200 smart frame throttling

[Felix <fx...@gm...>]

On Tue, 01 Oct 2002 11:59:31 +0100
Keith Whitwell <ke...@tu...> wrote:

> Felix Kühling wrote:
> > Hi r200'ers,
> > 
> > here is the improved frame throttling for r200. It compiles on my
> > system. Time for testing ...
> > 
> 
> I still get a lot of busy waiting with this patch.  I assume the behaviour is 
> the same on the radeon.  Run it against 'multiarb' from the mesa demos.  Every 
> second frame is busy waited, and cpu load is high.
> 
> The original irq_wait patch didn't have this behaviour, and I've committed a 
> version of that on the r200 now.
> 
> Keith

I just tried multiarb and it uses a bit more than 5% CPU on my Duron 900,
Radeon 7500 QW 64MB SDRAM, 24bit color depth.

Every second frame busy waited sounds like the effect I described with
usleep instead of busy waiting before. This can happen if the frame rate
is very high and the busy wait loop takes about as long as two frames.
If I guess correctly you may have to reduce the number of cycles in the
busy waiting loop or just say, it doesn't work with absurd frame rates.
I added a frame counter which is printed every 1000 frames to multiarb.
I estimate the frame rate to about 1150 fps. Since the r200 is a lot
faster and it draws only one QUAD that might be a problem. What happens
if you maximize the window ...

Felix

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