Real-Time Embedded Systems

11

 

 

Real-Time Scheduling Based on the Cyclic Executive

 

CONTENTS

11.1 Scheduling and ProcessModels

11.2 The Cyclic Executive

11.3 Choice of Major and Minor Cycle Length

11.4 Tasks with Large Period or Execution Time

11.5 Summary

In any concurrent program, the exact order in which processes execute is not completely specified. According to the concurrent programming theory discussed in Chapter 3, the interprocess communication and synchronization primitives described in Chapters 5 and 6 are used to enforce as many ordering constraints as necessary to ensure that the result of a concurrent program is correct in all cases.

For example, a mutual exclusion semaphore can be used to ensure that only one process at a time is allowed to operate ...