[Consortium] Benefit of Compiz to audio work?

Marc-Olivier Barre mobarre at gmail.com
Tue Nov 13 05:05:58 EST 2007

On Nov 12, 2007 6:21 PM, Pieter Palmers <pieterp at joow.be> wrote:
> Cory K. wrote:
> > The Ubuntu Studio team is considering shipping Compiz (with a minimal
> > config) in Ubuntu Studio-Hardy 8.08.
> >
> > Some have said that moving the drawing of windows off the the GFX card
> > would help the load on the CPU and thus keep xruns to a minimum.
> >
> > Any thoughts/ideas on this one?
> My stance would be that xruns are not that much dependent on load as
> they are on interrupts. If your machine is not at the maximum of its
> capabilities, xruns only seem to occur when certain I/O related events
> are happening. One of the most problematic I/O types in my experience is
> the video card I/O. So the question is whether you're not making things
> worse.
> When running a properly configured RT-patched kernel that prioritizes
> the video card IRQ low enough, it could be a good idea. When the config
> is bad, it will IMHO only increase the problems.

Since recently, I'm using compiz-fusion on my music laptop. Luckily,
my IRQs are not a bother as long as I don't use the internal sound
card :
 16:     150106   IO-APIC-fasteoi   uhci_hcd:usb5, HDA Intel,
radeon at pci:0000:01:00.0
 17:          7   IO-APIC-fasteoi   yenta, hdsp

Latency is set to 2.66ms. The most problematic clients causing runs on
my system are those unadapted to RT work (xmms2 and mplayer...) and
it's only a dozen/hour...

But still, I get a few random xruns that seem to happen without any
explainable cause... Not sure what they are. I'll have to dig a bit
more someday.
Marc-Olivier Barre,

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