[LAD] [Jack-Devel] JACK, cgroups and systemd

Dominique Michel dominique.michel at vtxnet.ch
Sun Jan 12 15:28:09 UTC 2014

Le Mon, 13 Jan 2014 00:22:40 +1100 (EST),
"Patrick Shirkey" <pshirkey at boosthardware.com> a écrit :

> On Sun, January 12, 2014 11:17 pm, Dominique Michel wrote:
> > Recently, I experimented with Debian sid, which use systemd. Systemd
> > idea is nice, but its implementation is a catastrophe. It is more
> > than one year I am using the kernel cgroups on gentoo to get rt
> > scheduling with JACK, that without any trouble.
> >
> > On Debian, this is just impossible, because whatever I try, systemd
> > insist to put what it think is good to have into the rt cgroup,
> > which soon or later result in a complete system freeze with even
> > dead magic keys. After loosing my time a few days with this, I
> > removed Debian and installed gentoo instead.
> >
> > I found the reason here:
> > http://article.gmane.org/gmane.linux.kernel/1063354
> >
> > "Lennart Poettering:
> >
> > Well, this feature is... completely irrelevant for normal desktop
> > people.
> > ...
> > In fact, I just prepped a patch to systemd to move every service and
> > every user session into its own cgroup in the 'cpu' hierarchy (in
> > addition to the group it already creates in the 'systemd'
> > hierarchy)."
> >
> > Another completely idiotic stuff of this guy.
> >
> > The point of the cgroups is it is possible to setup them for
> > whatever use will be made with a computer, and this guy think he
> > have the insane and pretentious capability to decide for every
> > single user of the use they will made with their computers, and he
> > is suggesting users doing something else are abnormal. He must be
> > stopped!
> >
> That patch is over three years old. It seems like you have found a
> loophole in the logic that was used to justify it.
> Granted, it's annoying but it just means we have to find a better
> solution.
> Similar to Fon's main objection to jack-session being *not flexible
> enough*. We all knew it would cause problems for specific use cases
> but we still haven't found a perfect solution to enable the
> flexibility that Fons identified while also allowing people to get on
> with the task at hand. Hence we have the less flexible but still
> useful for most use cases version of jack session.

With the cgroups, that flexibility exist. One of the main point
of the cgroups is to be flexible enough to be setup for any possible
use case. But with a systemd system, that flexibility doesn't exist
any more, because the only possible "normal" use case permitted by
systemd is to run a GUI (as stated by the "normal" one in charge of this

It is more than 1 year I use the cgroups within an openrc system,
and you can do whatever you want with the cgroups. The same apply for
sysv init system.

What made me mad in that story, is not because it is a bug into systemd
which made a kernel function to misbehave, I know very well that
the only one that doesn't make bugs is the one that doesn't make
code, but this is the complete lack of consideration for other needs
than what he consider to be the needs of a "normal desktop user". Which
strongly suggest users with other needs are abnormal users. Which in
turn imply that person is a racist when he suggest I am abnormal. And I
am not the only one, systemd will break any cgroup configuration for
any other use case than to run a GUI.


> --
> Patrick Shirkey
> Boost Hardware Ltd
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> Linux-audio-dev at lists.linuxaudio.org
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