[Consortium] Benefit of Compiz to audio work?

Ivica Ico Bukvic ico at vt.edu
Wed Nov 14 10:19:17 EST 2007

> > 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.
> I'm sceptical about that, because drawing windows shouldn't be causing
> xruns if the system is set up properly. I believe JACK Meterbridge uses
> libsdl for drawing the meter needles efficiently, but I believe most
> free software audio apps don't do much in the way of graphics
> acceleration (yet).

I think that is beside the point. AFAIK you still need to shuffle memory
around when moving widgets on the screen no matter what they are. Offloading
this to the GPU is a clear winner. That being said, there are still parts of
Compiz that rely upon the CPU (e.g. wobbly windows calculations).

> I can think of a number of drawbacks to using Compiz on audio machines
> though:
> 1. Reliance on proprietary drivers for systems that otherwise don't
> require them. OpenGL is unusable if you don't have hardware
> acceleration, and not everyone has a Matrox card.

The most dominant gpu on the desktop at the moment is Intel integrated video
card and that one runs Compiz arguably better than any other board.

> 2. Requirement for energy-hungry 3D cards (some of these cards need more
> electricity than CPUs which are perfectly usable for audio work). Apart
> from any environmental or cost considerations, more energy = more waste
> heat = more cooling noise. Which is bad in the studio, of course.

At DISIS we have built near silent machines from scratch with the following

C2D 2.67GHz
Nvidia 7600GT (or 8600GT)
2 x 250GB HD (RAID 1)

Video cards are not only fanless but are also lead-free. The entire rig is
cooled by a single <1200RPM fan including the PSU. Suffice to say that the
loudest part in the machine are HDs spinning idly. BTW, the case we use is
not one of those radiator aluminum rigs...

We use Compiz with all the bells and whistles in conjunction with FA-101
(Freebob). At 5.33ms I have not had a single xrun yet.

> 3. Electrical waste mountain. There are millions of machines out there
> which are perfectly (re)usable as audio workstations, but make Compiz a
> *requirement* for using free software, and they'll have to go into
> landfill.

I agree that compiz should not be a requirement. That being said, after
talking with Cory, my understanding is that Compiz would be used for very
basic stuff in its vanilla incarnation with most of the bells and whistles
disabled which should introduce performance advantages.

> Y'know, both OS X and Vista have gone down the power-hungry,
> new-hardware-or-forget-it route, and I'm not sure we need to follow them
> there.

Again, I agree to an extent. I am at a point where I want to have a pleasing
desktop experience. I am glad to say my ratpoison days are now over...

Best wishes,


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