PASS: Priority Assignment of Real-Time Tasks with Dynamic Suspending Behavior under Fixed-Priority Scheduling

Self-suspension is becoming an increasingly prominent characteristic in real-time systems such as: (i) I/O-intensive systems, where applications interact intensively with I/O devices, (ii) multi-core processors, where tasks running on different cores have to synchronize and communicate with each other, and (iii) computation offloading systems with coprocessors, like Graphics Processing Units (GPUs). In this paper, we show that rate-monotonic (RM), deadline-monotonic (DM) and laxity-monotonic (LM) scheduling will perform rather poor in dynamic self-suspending systems in terms of speed-up factors. On the other hand, the proposed PASS approach is guaranteed to find a feasible priority assignment on a speed-2 uniprocessor, if one exists on a unitspeed processor. We evaluate the feasibility of the proposed approach via a case study implementation. Furthermore, the effectiveness of the proposed approach is also shown via extensive simulation results.