Real-Time Embedded Systems

Chapter 15

Real-Time Scheduling

Clock-Driven Approach

Abstract

While in Chapter 13 we glimpsed several task scheduling policies, in this and the next two chapters we will take a deeper look at three scheduling approaches widely adopted in various real-time applications. Cyclic scheduling is an approach to scheduling periodic tasks according to a static schedule table precomputed off-line. The schedule table specifies exactly when each job executes. While the clock-driven approach uses a schedule table containing one entry for each job, the schedule table used by frame-based scheduling has a better structure. If the frame size is selected carefully, a frame-based schedule will allow the scheduler to check the timing constraints at a frame ...