kernel-rt-3.10.0-693.11.1.rt56.632.el7 with lower kernel.sched_rt_period_us

Issues related to applications and software problems
Post Reply
jjj
Posts: 2
Joined: 2018/12/04 12:43:49

kernel-rt-3.10.0-693.11.1.rt56.632.el7 with lower kernel.sched_rt_period_us

Post by jjj » 2018/12/04 14:11:21

hi,

I'm trying to get the rt kernel working. I need a lower kernel.sched_rt_period_us because my highest prio rt tasks cannot be blocked for 50ms. Therefore I try to run with kernel.sched_rt_period_us = 1000 and kernel.sched_rt_runtime_us = 950 (in the past I used the same values with a rt patched 3.4 kernel without issues). These settings are applied by an entry in the /etc/sysctl.d/ folder. Unfortunately now my system boot is unstable, every few power cycles I get an error message "failed to start apply kernel variables" and the system takes a long time to boot. After that the system appears OK and the settings are applied; systemctl status systemd-sysctl.service does not give me any info.

Any help would be greatly appreciated.

jjj
Posts: 2
Joined: 2018/12/04 12:43:49

Re: kernel-rt-3.10.0-693.11.1.rt56.632.el7 with lower kernel.sched_rt_period_us

Post by jjj » 2018/12/05 10:39:27

looks like these variables are applied twice

and sometimes the first time only kernel.sched_rt_runtime_us = 950 gets applied. apparently the variables get applied in random order even if I split them into separate files?? in this case the boot sequence takes a long time. after a minute or so in the second pass the kernel.sched_rt_period_us = 1000 gets applied too and after that the system behaves normal again ...

Post Reply