[LAD] [OT] Real-time threads on openSuSE 11.4

[Bengt Gördén]

2012-10-19 15:02, Fons Adriaensen skrev:
> Hello all,
>
> My ex-collegues at Alcatel are screaming for help. They want to run
> an app (as root, debatable but that's another story) using SCHED_FIFO
> threads on an openSuSE 11.4 system.
>
> Using the 'default' kernel (which has CONFIG_PREEMPT not set), this
> works. Using the 'desktop' kernel (CONFIG_PREEMPT=y) they get an
> EPERM when trying to start a RT thread, even as root.
>
> As I haven't used SuSE for ages, has anyone an idea of what is
> happening here ?

Try with chrt.

On my laptop with opensuse 11.4 with desktop-kernel. I started "top" as 
root.

linux-do4z:~ # ps -up `pidof top`
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root     15666  0.4  0.0   8848  1300 pts/19   S+   17:54   0:00 top

linux-do4z:~ # chrt -p `pidof top`
pid 15666's current scheduling policy: SCHED_OTHER
pid 15666's current scheduling priority: 0

linux-do4z:~ # chrt -f -p 20 `pidof top`

linux-do4z:~ # chrt -p `pidof top`
pid 15666's current scheduling policy: SCHED_FIFO
pid 15666's current scheduling priority: 20

check with "chrt -m" for priorities.

regards,

/bengan