On 7 Nov 2010, at 18:36, Hans-Christoph Steiner wrote:
As far as I understand it, Pd only does the 20% idle thing when its not really doing anything. So if Pd is working hard, it'll stop spending 20% of the CPU idling. I could be wrong tho, and that would be worth profiling. That's the key point: is Pd efficient when its doing stuff, rather than whether it uses extra CPU when idling.
- Pd uses X% of the CPU talking with audio drivers when it is idle (even if audio is off)
- When the audio driver is portaudio Pd uses ~20% of the CPU talking with the driver (under OS X on a 2.5 GHz MBP)
2 separate problems, the second being the most pressing.
And yes, ~20% is the base level, so as soon as you start adding processing, CPU load goes up from there...
I don't think portaudio is that great for realtime work, although I think this is bordering on worst-case (compared to other apps). I've a feeling the problem might lie in the buffer size used for passing audio to portaudio.
Jamie