Scheduling Low-Utilized Distributed Real-Time Systems with End-to-End Timing Constraints

End-to-end delay is one of the most important timing constraints in distributed real-time systems (DRTS), especially in the area of wireless sensor network (WSN) or Internet of Things (IoT), which has many nodes in the system. The distributed pinwheel scheduling algorithms have been designed to schedule tasks with distance constraint and end-to-end delay. However, distributed pinwheel scheduling algorithms provide simple scheduling bounds and approaches only for fully utilized tasks. We find there exists a simple feasible algorithm with scheduling bound, and it results in shorter end-to-end delay in many low-utilized cases, compared with distributed pinwheel scheduling algorithms. We also analyze the effect of the relative length of execution times on end-to-end delay, and schedulability. We believe ASr has large potential in shorter end-to-end delay and easier use, especially in low-utilized DRTS, which commonly presents the case of WSN or IoT.