rt kernel

Victor henri nadaeck at hotmail.com
Sun Apr 3 12:15:00 UTC 2011


> On 04/03/2011 08:44 AM, Victor henri wrote:
> > It seems that the -generic kernel in Ubuntu 10.10 (and 11.04) is not very appropriate for that, since the RT_GROUP_SCHED option in the kernel is enabled; it means that it overrides everything that may have been configured in the limits.conf. See jackd FAQ : http://jackaudio.org/linux_group_sched
> > This seems specific to Ubuntu (according to Jackd FAQ); so it's probably worth to have a try, but you shouldn't be surprised if you have a lot of Xruns. Then you should considerr other options (see below)
> >
> The cgroups thing is no longer an issue. The information on Jacks page
> is no longer up to date. We should ask them to remove that part from
> their FAQ.
> 10.10 was never affected.

But when I 'sudo make menuconfig' in the /usr/src/linux-headers-2.6.35-22-generic directory (or the -28-generic) the RT_GROUP_SCHED option is enabled...

 On 11.04 kernel version 2.6.37 was not usable
> without having to recompile it, but the kernel in Natty is now 2.6.38,
> which includes a patch that removes this problem.

Is a patch needed for that? Is it not enough to disable the RT_GROUP_SCHED option then compile or recompile?

> The performance on 2.6.38 has been going up and down during the
> development of Natty. At the moment, it is not bad, though not perfectly
> reliable.
> Alessio Boganis PPA includes a -lowlatency kernel for Natty, which
> performs virtually as well as a -realtime kernel would, for *most* people.

Yes indeed, I've noticed that; It was such a big and nice surprise to see that a 2.6.37 or 2.6.38 preempt could do almost the same job as a realtime kernel (at least for what I do) 
> --
> ailo



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