Real-time priority

Guenter Geiger guenter.geiger at
Tue Apr 6 14:30:23 CEST 1999

Hi Larry !

Actually , when writing about solving the realtime scheduling problem,
I was thinking about your proposal, which, I think you posted over
a year ago on the list.

With this solution it would be possible to reliably run pd under root.
We could check the performance of the system and switch to normal
scheduling, when we realize that pd uses more than, say 95% of the CPU.

I found out, that with some Computer - Soundcard combinations, pd runs
very well under root, but "clicks" when run as normal user.

A reliable solution for high priority scheduling  should give us better
at least under Linux and SGI, so we should try to find a common solution for


> -----Original Message-----
> From: root at [mailto:root at]On Behalf Of Larry
> Troxler
> Sent: Thursday, April 01, 1999 5:42 PM
> To: pd-list
> Subject: Real-time priority
> Hi, I haven't been using PD lately, but thought but the
> recent messages
> about running PD as root insterested me.
> I assume that PD grabs the Posix real-time scheduling algorhihm when
> running as root.
> Once, when playing around with the some other real-time audio code, I
> was able to use a second thread as a sort of software watchdog.
> The watchdog thread would run periodically, checking and clearing a
> global flag that the audio thread would write everytime it
> completed its
> output generation loop. The watchdog thread ran one priority level
> higher than the audio thread.
> This was a while ago, but I remember that the concept seemed
> to work. Am
> I missing something with this idea?
> Larry
> --  Larry Troxler --  lt at  --  Patterson, NY USA  --

More information about the Pd-list mailing list