Hello. I have a long running process on a server running Ubuntu Server 9.10. I would like to make it run under the SCHED_IDLE policy using the chrt command. However, after reading the man page, I can't manage to understand the proper way to issue the command for a running process.

I've tried unsuccessfully:

# chrt -i -p 688
pid 688's current scheduling policy: SCHED_OTHER
pid 688's current scheduling priority: 0
# chrt -p -i 688
pid 688's current scheduling policy: SCHED_OTHER
pid 688's current scheduling priority: 0
# chrt -p 688 -i
chrt: failed to set pid 0's policy: Invalid argument

I'll keep trying, but do you know how to do what I want?