[LAT] 2.6.29-rc4-rt2

Emanuel Rumpf xbran at web.de
Sat Feb 14 16:31:44 EST 2009

2009/2/14 Emanuel Rumpf <xbran at web.de>:
> My problem:
> jack doesn't start with the real-time option enabled - output:
> JACK compiled with System V SHM support.
> cannot use real-time scheduling (FIFO at priority 10) [for thread
> -1210911056, from thread -1210911056] (1: Operation not permitted)

Ah ... fine !
At LAU-ML, I found a message (02.02.2009) by Robin Gareus,
which solves the problem:

`echo -1 > /proc/sys/kernel/sched_rt_runtime_us`

or edit /etc/sysctl.conf and add:
kernel.sched_rt_runtime_us = -1

and his comment:
indeed, jackd did not start unless run as root or until I changed

It's the us (or .001% of CPU usage?!) above which FIFO and RR will be
throttled to recover from a run-away rt process. - I'm not exactly sure
why it affects jackd when run as "normal" user; maybe because with CPU
load above the default 95% rt can not be guaranteed.

There's a bit [off topic] but enlightening info at



Emanuel Rumpf

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