Hi all -
The following magic seems to work on any linux distribution: edit /etc/security/limits.conf and add the lines,
- rtprio 99
- memlock 1000000000
I can't remember if I did this on my Pi or not (and don't have it handy right now to check) but I bet I did.
On the other hand, I wonder what Pd extended does. Perhaps it makes itself belong to group 'audio' and runs 'rwxr-sr-x' (the 's' meaning that it confers its group status to whomever runs it). But I thought the 'pi' user was already part of group audio. Also I'm not sure if group audio gets realtime permission by default on Raspian - that's another thing I'd need to dig up my pi to check...
cheers Miller
On Sun, Nov 30, 2014 at 03:12:10PM +0100, katja wrote:
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 headless).
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: http://lists.puredata.info/pipermail/pd-list/2014-11/108543.html). 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.
Katja
Pd-list@lists.iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list