Realtime Priority Thread For Alsa - Missing PAM HowTo

Help, Support & Bugs
1

Hi Guys,

First of all, thanks for your help in resolving the last issue I posted about.

Currently, every time I load Renoise (or initialize the audio engine), I get an error that says

Error Message: Failed to create a RealTime priority thread for ALSA. Will create a non RT thread instead...  
Error Message: Its highly recommended to use RealTime priority audio threads with ALSA AND JACK to get accepteable audio latencies, but you may need admin rights to create RT threads. Please see the Renoise for Linux FAQ on http://tutorials.renoise.com for more details...

I suspect that this is an error in my PAM configuration, but the FAQ currently contains no references to PAM, and the references to realtime priority in the FAQ are only (as I understand it) applicable to v1.9.1.

2

Hi Probable,

Have a look at http://tapas.affenbande.org/wordpress/?page_id=73 for now. We had a section about PAM in the FAQ, but now it seems to be gone. We should of course add it again…

3

I did not removed the PAM questions in the FAQ (didn’t know if they were ever in it either by the way) . Perhaps Neurotix did because PAM modifications should not be an ordinary user’s concern and considered Renoise it’s automatic PAM arrangement sufficient enough to remove the information.

4

Okay, i’ve noticed what Taktik meanted.

For the answers to your questions i’ve added the missing information that was clumsely overwritten by me and now with two direct bookmarks to the questions in matter:

http://tutorials.renoise.com/Renoise/SettingUpLinux#PAM
http://tutorials.renoise.com/Renoise/SettingUpLinux#PAMTWO

5

Those Links there are all dead.

Please checkout the Renoise-FAQ
https://tutorials.renoise.com/wiki/Linux_FAQ

Realtime Threads

How do I configure Linux to enable Realtime Threads for ALSA or Jack?

Realtime threads are required for low latencies with ALSA and Jack, and to enable them you have to edit the /etc/security/limits.conf file. Simply running a realtime kernel does not help here, since it doesn’t automatically set the required options. To enable RT thread creation via PAM, open the /etc/security/limits.conf file as root (or via sudo) and add the following lines to the end of the file:

YOURUSERNAME - rtprio 99

YOURUSERNAME - nice −10

Alternatively, you could create a group ‘Audio’, add your user to that group and then use ‘@Audio’ instead of “YOURUSERNAME”. After this, you should save, log out and then log back in. To make sure this has worked, launch Renoise, select ALSA and ensure that the ‘Realtime threads’ option is enabled. You will get a friendly warning if RT creation failed. You can find a more detailed explanation about PAM and low latencies in Linux here: http://tapas.affenbande.org/wordpress/?page_id=73.

Also, see System configuration [Linux-Sound] for more information and tips on how to build and tweak a real-time audio Linux workstation.