The rtprio directive is used to specify the priority at which Heartbeat runs. It does not need to be specified unless other realtime priority programs are also running on the system. The minimum and maximum values for this field can be determined from the sched_get_priority_min(SCHED_FIFO) and sched_get_priority_max(SCHED_FIFO) calls respectively. The default value for rtprio is halfway between the minimum and maximum values.
A sample rtprio directive is shown below: