Quasi-Dynamic Scheduling for the Synthesis of Real-Time Embedded Software with Local and Global Deadlines

Often real-time embedded software is specified as a set of interacting tasks that have local deadlines on subtasks and global deadlines on each task. Currently available scheduling algorithms guarantee only a single level of deadlines, either all local or all global, but not both. We propose a quasi-dynamic scheduling algorithm for simultaneously guaranteeing both types of deadlines, while satisfying all precedence constraints among subtasks and among tasks. Through this scheduling procedure, we are able to formally synthesize real-time embedded software from a network of Periodic Time Petri Nets specification. Application examples, including a driver for the Master/Slave role switch in Bluetooth wireless communication devices, are given to illustrate the feasibility of the scheduling algorithm.