Low power system scheduling, synthesis and displays

Low power system synthesis, specifically, system-on-a-chip (SoC) synthesis and hardware-software co-synthesis of distributed embedded systems, has attracted much attention. The system may be wireless and may have both quality of service (QoS) and real-time constraints. We will discuss such synthesis techniques in this chapter. A significant fraction of the software and resource usage of a handheld computer system is devoted to its graphical user interface (GUI). GUIs are direct users of the display. They enable users to interact with the software. Since displays often are the greatest energy-consumers in such systems, it is important to optimise GUIs for energy. In addition, dynamic voltage scaling (DVS) and dynamic power management (DPM) techniques have traditionally been applied to computation and I/O intensive tasks. However, many modern applications are interactive in nature, necessitating new DVS/DPM techniques that take into account the user's perspective. Display power can be directly targeted by optimising the power of its various components. We discuss low power system scheduling, synthesis and interactive systems in Sections 11.2, 11.3 and 11.4, respectively. We point out some open problems and conclude in Section 11.5.