[LAU] changing ulimit from rc.local in order to start audio scripts from there

Len Ovens len at ovenwerks.net
Mon Oct 9 23:08:40 UTC 2017

On Mon, 9 Oct 2017, Athanasios Silis wrote:

> Hi there,
> I have setup an audio system around jackd based on ubuntu studio (14.04 LTS). I
> have written various scripts to setup jackd and clients. It is tested and up
> running. Now I would like to add a cmd in rc.local in order for the whole system
> to be brought up at boot.

Be aware that some startup stuff has a timer in it. The setting of 
ondemand happens 60 seconds after it's startup is run as an example... at 
least in debian derived stuff.

Installing jackd properly (rt permissions answer yes) should set this 
stuff up for you anyway.

> However the ulimit "set" command fails with message
> ulimit: real-time priority: cannot modify limit: Operation not permitted
> I read that ulimits are not ready yet at this time. Is there a way to forcefully
> "bring them up" in order to have them set for the user "nass" before starting the
> audio scripts ??

Use sleep 70 at the start of your script? Make sure you are giving nass a 
login shell may also help. You may have to set environmet variables first 
as well. Make sure nass is in the audio group or whatever your distro uses 
to give rt permissions.

I do not know if these things will help, I have run a headless session 
complete with dbus, pulseaudio, jackdbus and various other audio 
applications... I really didn't need PA and therefore could have run 
without the dbus stuff. It was more of an experiment to see what I could 
do and the headless box had less than 1/4Gb of ram anyway, so it was not 
practical for real use. I should try setting up a headless jackd box on 
something newer though where I can make real use of it.

Len Ovens

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