RTEMS 4.9.0 On-Line Library

Rate Monotonic Manager Processor Utilization Rule Example

RTEMS C User's Guide

19.2.5.3: Processor Utilization Rule Example

This example illustrates the application of the Processor Utilization Rule to an application with three critical periodic tasks. The following table details the RMS priority, period, execution time, and processor utilization for each task:

Task	RMS Priority	Period	Execution Time	Processor Utilization
1	High	100	15	0.15
2	Medium	200	50	0.25
3	Low	300	100	0.33

The total processor utilization for this task set is 0.73 which is below the upper bound of 3 * (2**(1/3) - 1), or 0.779, imposed by the Processor Utilization Rule. Therefore, this task set is guaranteed to be schedulable using RMS.

RTEMS C User's Guide