On 12/13/2010 09:34 PM, Ronan Jouchet wrote: > Hi Ubuntustudio-devel, Ubuntu-kernel, JACK-devel, Alessio, > > After talking with adi in #ffado and las in #jack, it appears that > Natty's kernel needs adjustment to be usable for audio work. Currently > the kernel flavors shipped by Ubuntu have the RT_GROUP_SCHED option > activated, which makes JACK unusable (las put up > http://jackaudio.org/linux_group_sched to sum up the situation). > > *Until this problem is solved, JACK is unusable under Natty*. Las > mentioned several solutions: > 0. Disabling RT_GROUP_SCHED for all kernels > 1. Disabling RT_GROUP_SCHED for the kernel targeting audio users > (-lowlatency, currently living in abogani's PPA) > 2. Set up a cgroup and invoke JACK and every client from a shell > script that joins the cgroup first > 3. Use cgrules.conf to at least put processes into the right group by > default > 4. Use Ubuntu's specific mechanism to put user tasks into a > RT-enabled cgroup > > Quoting las: "(1) is the desirable option; (2) would be next and (3) > would be hard, because it would enforce 'application<foobar> always run > in the<bazbar> cgroup' which is not really very useful or correct". (0) > may also be considered since this kernel option is apparently very > specialized for embedded systems and doesn't make sense for a desktop > distro. > > Which path should be followed is beyond my knowledge. I just hope this > discussion will pave the way to a usable audio stack in Natty. > > Resources: > LP bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/690010 > IRC : #jack, #ubuntustudio, #ubuntustudio-devel > IRC log of my discussion with las: http://pastebin.com/2yw7aPhr > > All the best, >
I'm not opposed to disabling RT_GROUP_SCHED. After all, it _is_ marked EXPERIMENTAL. Have you proven that a kernel with RT_GROUP_SCHED disabled actually fixes the issues that you're seeing with JACK ? rtg -- Tim Gardner [email protected] -- Ubuntu-Studio-devel mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-devel
