Realtime for Ardour and Jack

English Multimedia
1

Hi, I recently installed Ardour.
The Jack backend requires realtime.
How do I give a process realtime previliges?..

Leap 15.0 runs PAM, rtkit, polkit … have no idea how to use these programs.

thanks for your help

2

It is not privileges it is how the kernel runs you need a realtime kernel

3

For my Music Production purposes, I use a dedicated distro: In my case, AV Linux, but there is also KXStudio.

4

thanks for the replies.

1st. I think the guys from Ardour/Jack have a watered down version of realtime in mind. I sofar had not any luck to get further info. In my system when start an new Ardour session using Jack it failed. When using alsa it is ok.
I need however to run Jack because Jack can handle various sound programs.

2nd . Not a bad idea. Did you install Suse and linux studio SW on the same hardware ? If yes how to ?

If you have further ideas that would be great.

cheers

5

Be sure you have pulseaudio_module-jack package to run jack on top of PA. If you must have real time you need a real time kernel. But modern kernels on modern CPU are pretty much “real time”

6

In Leap 42.3 it was possible to do this with the standard kernel, but it seems to be broken so i’ve created a bug report https://bugzilla.opensuse.org/show_bug.cgi?id=1100734

7

I am running Ardour and Jack on Leap 15. It works Ok, but there are some xruns. I tried many things, and although my platform is an 8 core AMD Fx 8310 CPU, and 32GB RAM, 500 GB SSD, I do not think a modern system is sufficient, in itself. I do think the realtime Kernel is necessary for the low latency needed when recording. I mainly use the PC for 4k Video editing in KDENlive, and it works fine for that. But that is not realtime. I did disable Pulse and the Xruns dropped considerably. Running Jack with 1024 Frames and 3 Periods per buffer. Jack shows a latency of 64 ms, and Ardour shows 21 ms. This is not perfect but is low enough for what I do. Non professional recording of my own music.
Ardour 5.12.0
Jack 0.4.3
Alsa 1.1.5-lp150.5.6.1
Added Calf plugins, etc.

8

FWIW: I use Ardour on Leap 15 with Jack, and found ( lost the original link ) that it needed this


# Ardour stuff
@audio - rtprio 95
@audio - memlock 512000
@audio - nice -19

in /etc/security/limits.conf

Heaven’t measured latency though, but I’m quite satisfied with how it works now.

9

mine is at rtprio 99
and nice -10
Memlock unlimited

Perhaps a lower nice value will help

Tks

10

Did not work at -19. A few xruns still occur.
I will leave it at that.