Jitter control in time-triggered systems

The paper addresses the jitter control issue in time-triggered real-time systems where tasks are activated according to time. Our model is based on the temporal distance constrained task model (DCTS). However, many real-time systems have tasks that do not fit the simple assumptions of the DCTS model because tasks may occasionally access shared resources, and certain tasks may arrive irregularly. We address the issues that cause jitters in DCTS. We first review the algorithm developed for DCTS and present an extension for an optimal algorithm. Three jitter issues are then discussed: sharing resources between tasks, handling tasks that have fixed and unchangeable periods, and handling tasks that arrive aperiodically. We present solutions that can prevent jitters, as well as other solutions that may result in minor jitters.