[PD] High CPU usage when tracks are muted (Raspberry Pi)

Halfdan Mouritzen halfdan at robothangarskib.dk
Sun May 5 18:11:56 CEST 2013

Dear PD Friends,

We are building a collaborative music sculpture, using five Raspberry
Pi's to each run a seperate instrument / HID.
Everything is very well, they each run a minimal Arch installation and
boot up into PD without a GUI.

One machine we are building at the moment, is just a very basic sample
player - it has 8 tables with samples, that get played via a looping
The machine works by simply muting and unmuting of the different
channels - very basic.

Now the problem is that when all eight tracks are unmuted the CPU
usage is around 15-16 % - very fine, with lots of room for other
NOW, when one mutes channels, the CPU usage starts climbing and
climbing, resulting in 95-100% usage when all the channels are
This results in lagging/glitching, when one tries to turn on channels again.
The muting / unmuting is done through a simple *~ which gets set to
either 0 or 1 with a line.

I have noticed others have experienced this problem, but I haven't
been able to find a solution to the problem.
Hope somebody has a solution, as we are installing the machine at a
music festival this week, and plan to open source all
patches/sounds/build plans etc.

All the best and keep on patching
Halfdan & Jonathan

More information about the Pd-list mailing list