An Efficient Scheme to Allocate Soft-Aperiodic Tasks in Multiprocessor Hard Real-Time Systems
J.M. Banús, Àlex Arenas, Jesús Labarta · 2002
We propose a scheme to allocate individual softaperiodic tasks in a shared memory symmetrical multiprocessor for hard-real time systems applications. The aim of this scheme is to minimize the aperiodic mean response time by running a local uniprocessor scheduler to serve periodic tasks guaranteeing their deadlines, and serving aperiodic tasks with a global scheduler that uses different allocation strategies. We show that performance achieved depends highly on the allocation decisions made by the global scheduler when several processors are available to execute aperiodic tasks. We compare four classical allocation strategies and the best results are obtained using a next-fit allocation strategy. The mean aperiodic response time with this strategy is less than 2 times the computation time required by the aperiodic tasks, up to total loads of 97%.