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

From: Kaj Ailomaa <zequence@email-addr-hidden>
Date: Fri Sep 07 2012 - 06:19:18 EEST

On Fri, 07 Sep 2012 04:31:36 +0200, Ralf Mardorf
<ralf.mardorf@email-addr-hidden-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
>
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Received on Fri Sep 7 08:15:02 2012

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