On Wed, 30 Dec 2015 15:01:56 +0100, Maarten de Vries wrote:
Lack of compositing has nothing to do with rendering on CPU or GPU. Applications can still get an opengl context and render things. Compositing simply means that the applications wont be rendering to a directly visible buffer but to a buffer that is used by the compositor. That way it can add effects and eye candy. If anything, lack of compositing will increase performance by cutting out the middleman and having applications render directly to a visible buffer.
This explains why without compositing performance doesn't slow down and that it could have a positive effect and not a negative one. Compositing might cause xruns for audio signals or at least might increase MIDI jitter. At best it doesn't affect audio and/or MIDI, but if it affects audio and/or MIDI, then it would make it work worse. Each additional interrupt could cause issues. If audio or MIDI signals are delayed by a fixed time, that isn't too long, it's possible to adjust this without causing an issue. If timing too much fluctuates randomly, this could cause serious trouble. I suspect that CNC machines are more prone to jitter, than MIDI is.