Controlled duplication for scheduling real-time precedence tasks on heterogeneous multiprocessors

Duplication based heuristics have been used for scheduling precedence constrained tasks with significant communication in them. Duplicating heavily communicating subtasks of a task on to the same processor improves the schedulability as a larger number of tasks meet their deadlines. However, this reduction comes at the cost of extra computing power required for duplicating subtasks. In this paper, we propose a novel real-time controlled duplication based heuristic called RTCDA for scheduling such tasks on heterogeneous multiprocessors. We observe that duplication is not always required. The decision whether to duplicate or not is decided by the deadlines of the tasks. If a task can meet its deadline without duplication, then it creates more schedule holes and vice versa. RTCDA can utilize these schedule holes to improve the success ratio. Simulation results show that the proposed algorithm gives a better performance than other similar algorithms.