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