[PD] Raspberry Pi & pd 0.46 with real time priority

katja katjavetter at gmail.com
Sun Nov 30 15:12:10 CET 2014

Without real time priority, Pd on Raspberry Pi easily suffers from
drop outs. When I run vanilla Pd (for example 0.46-2 executable from
Miller's site http://msp.ucsd.edu/software.html) on Raspbian with
option -rt, it says that priority scheduling failed, and 'audio I/O
error' flashes whenever I move the cursor (I'm not running the Pi

I've noticed that puredata 0.43 as installed from Raspbian repository
can run with real time priority even when started by normal user. I
wondered where the difference is: in the Pd version or in the fact
that puredata from repository is installed and owned by root. Or maybe
yet another factor that I can't think of. In any case, I built and
installed puredata 0.46.2 from repository source (described here:
This build works with normal user real time priority too.

In order to see if ownership matters, I changed ownership of Miller's
build to root. Still it can't run with real time priority when loaded
by normal user. Permissions are the same for Miller's build and
puredata from repository (-rwxr-xr-x).

Does anyone know a way to run Miller's build with real time priority
(apart from running with root permission, which I don't want)? Though
I'm happy with puredata 0.46.2 as built from repository source, there
may sometimes be a reason to use or test another build.


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