Research and Design of a Deadline Monotonic Based Hybrid Tasks Real-time Static Priority Scheduling Algorithm
Jiwen Dong · Shandong kexue · 2010
Hybrid scheduling of hard periodic and soft aperiodic task is a key issue of real-time scheduling.We present a new static priority scheduling algorithm PADM(Periodic and Aperiodic Deadline Monotonic) for this issue,which is based on the property of modern embedded real-time system and the characteristic of only scheduling for a period task of the classical real-time scheduling algorithm.The algorithm employs DM(Deadline Monotonic) and FCFS(First Come First Served) to quantify an aperiodic task into a period task,and the priority of an aperiodic task is the highest when its laxity is zero.Our experiments show that PADM can guarantee the finish rate of a periodic task and the time deadline of an aperiodic task when task load is light.It also has less overhead and lower computing complexity.It is easy to be implemented.PADM is therefore an effective hybrid tasks scheduling algorithm.