Self-suspension real-time tasks under fixed-relative-deadline fixed-priority scheduling

Self-suspension is becoming a prominent characteristic in real-time systems such as: (i) I/O-intensive systems (ii) multi-core processors, and (iii) computation offloading systems with coprocessors, like Graphics Processing Units (GPUs). In this work, we study self-suspension systems under fixed-priority (FP) fixed-relative-deadline (FRD) algorithm by using release enforcement to control self-suspension tasks' behavior. Specifically, we use equal-deadline assignment (EDA) to assign the release phases of computations and suspensions. We provide analysis for deriving the speedup factor of the FP FRD scheduler using suspension-laxity-monotonic (SLM) priority assignment. This is the first positive result to provide bounded speedup factor guarantees for general multi-segment self-suspending task systems.