Hello! > I'm re-styling the demudi tasks packages, which I'd like to upload to > Debian in the near future. One of them it's called demudi-config and > it's haevily based on the debian-edu-config package. It uses cfengine > to customize configuration files in a consistent manner. > > As already discussed, we are going to drop the demudi specific version > of the jack package, and rely on the debian one. > > I was wandering about which tunings are needed to the enhance the > performance of jackd, and whether they should be accomplished through > the demudi-config task or directly with jackd. > > The ones that come to my mind are: > > 1) Turn on low latency: > > echo 1 > /proc/sys/kernel/lowlatency
using /etc/sysctl.conf is nicer than this. > This assumes a patched 2.4 kernel, which AFAIK is not the case of > the official Debian kernel. True. Are you going to upload the DeMuDi Kernel to Debian? > I don't know whether the 2.6 series need such tuning too.. There are now lowlatency patches (in this form) for 2.6. There is PREEMPT and in the ck-patches there is a very interesting isochronous scheduling mode. > 2) Setuid the jackstart binary. This can be accomplished via > dpkg-statoverride (as suggested in the README.Debian of jackd), but > I'm not sure whether the best solution is: Why don't you all subscribe to the jack-audio-connection-kit package on <http://packages.qa.debian.org/j/jack-audio-connection-kit.html>? JACK (>= 0.94.0-2) does contain jackstart setuid root, executable by group audio. dpkg-statoverride is only if you want to _override_ permissions. > a. Add debconf support to the jackd package and ask a question, for > example "Do you want jackstart setuid?", if the the answer is > positive the postinst script takes care of running > dpkg-statoverride. In this case the demudi-config package would > just inject the appropriate value in the debconf database. > > b. Do a. but through the demudi-config package, maybe without the > question, as we assume a positive answer. > > c. Do not setuid the jackstart binary, but rather prepare a 2.6 > kernel for DeMuDi (I'm assuming that Debian is not going to adopt > such patch in the short term), using the Jack O'Quin's kernel Someone should just _package_ that module! > module. The demudi-config package could make sure that such module > is loaded in the correct way and ask which users should belong to > the audio group. > > 3) Mount /tmp as a tmpfs, adding the line > > none /tmp tmpfs defaults 0 0 > > to fstab. Again this can be accomplished both inside demudi-config > and inside jackd and I'm not sure which place is better. Also done. libc6 >= something-ds11 mounts a shmfs onto /dev/shm. JACK (>= 0.94.0-2) puts its files there. > 4) Write a ~/.asoundrc file (for users in the audio group). I don't > know if this is really necessary, but it can be accomplished by > demudi-config. No. I don't think it's necessary. jackd defaults to hw:0, which makes sense. Robert. --
