[LAU] how to inable real time sheaduling for audio work?

[Kaj Ailomaa]

On Fri, 07 Sep 2012 04:31:36 +0200, Ralf Mardorf  
<ralf.mardorf at alice-dsl.net> wrote:

> On Fri, 2012-09-07 at 01:34 +0100, trahern culver wrote:
>> hey all i've tried to do this on my own and failed :( so my question to  
>> you all is this how do you enable real time scheduling for audio work  
>> in ubuntu?
>>
>> your help with this question would be most welcome kind regards trahern.
>
> Install the Ubuntu Studio meta packages, they'll set up your machine

In short, if you want to get realtime scheduling with jack, install jackd  
and linux-lowlatency, and add yourself to audio group.

The ubuntustudio meta packages will only install software, and will not  
enable realtime privilege
To do that, you need to do two things. First, answer yes when asked about  
it when installing jackd. (To double check, make sure the file  
/etc/security/limits.d/audio.conf is not named  
/etc/security/limits.d/audio.conf.disabled. If so, rename it).
The second required step is to add the user to audio group, which can be  
done with: sudo usermod -a -G audio $USER.

Remember to reboot.

> some optimization still might be needed. If they shouldn't install the
> low latency kernel, install this kernel too. To the grub.cfg or menu.lst
> add "threadirqs", e.g.
> kernel /boot/vmlinuz-3.0.30 \
> root=UUID=338316fb-364e-4a43-8deb-738127f878ce ro quiet threadirqs"
>

The threadirqs option is only required for the linux-generic kernel, since  
it's hardcoded into linux-lowlatency.
This is needed if you are going to be using the rtirq-init package, which  
includes the rtirq script.
If wanting to add threadirqs manually, a simple way to add it for all  
kernels is in the file /etc/default/grub.
Just add threadirqs to the line:
GRUB_CMDLINE_LINUX=""
so it reads:
GRUB_CMDLINE_LINUX="threadirqs"



> Regards,
> Ralf
>
> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user at lists.linuxaudio.org
> http://lists.linuxaudio.org/listinfo/linux-audio-user