Schedulability analysis in hard real-time systems under thermal constraints

In this paper, we study thermal-constrained hard real-time systems, where real-time guarantees must be met without exceeding safe temperature levels within the processor. Dynamic speed scaling is one of the major techniques to manage power so as to maintain safe temperature levels. As example, we adopt a reactive speed control technique in our work. We design an extended busy-period analysis methodology to perform schedulability analysis for general task arrivals under reactive speed control with First-In-First-Out (FIFO), Static-Priority (SP), and Earliest-Deadline-First (EDF) scheduling. As a special case, we obtain a closed-form formula for the worst-case response time of jobs under the leaky-bucket task arrival model. Our data show how reactive speed control can decrease the worst-case response time of tasks in comparison with any constant-speed scheme.