[PD] latest Pd-Extended cpu usage (was: new editing features of Pd-extended 0.43, now in beta)

katja katjavetter at gmail.com
Tue Feb 28 22:10:42 CET 2012

On Tue, Feb 28, 2012 at 9:06 PM, Jamie Bullock <jamie at postlude.co.uk> wrote:

> Yup, I think this is related to the Portaudio driver. I reported it here:
> http://sourceforge.net/tracker/?func=detail&aid=3100679&group_id=55736&atid=478070
> I don't think it's Portaudio itself that's at fault, but rather the way it
> interfaces with Pd.
DspFuncLib is in:


If you run command nm on the lib, you'll see a plethora of dsp functions
like MultiBandCompressor, NoiseCanceller, Loudness, Softclip, Limiter and
whatnot. Functions in this lib are called when the internal soundcard is
used. When using an external soundcard with Pd, DspFuncLib is not called
and that makes the big difference in CPU load.

AppleHDA and mach_kernel are Apple libs as well and together
with DspFuncLib they are responsible for the crazy CPU load in the
'idle-but-dsp-on' case.

PortAudio functions are apparently statically built into Pd and they
consume very little CPU time.

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