Abstract
Power-aware systems are those that must exploit a wide range of power/performance trade-offs in order to adapt to the power availability and application requirements. They require the integration of many novel power management techniques, ranging from voltage scaling to subsystem shutdown. However, those techniques do not always compose synergistically with each other; in fact, they can combine subtractively and often yield counterintuitive, and sometimes incorrect, results in the context of a complete system. This can become a serious problem as more of these power aware systems are being deployed in mission critical applications. To address the problem of technique integration for power-aware embedded systems, we propose a new design tool framework called IMPACCT and the associated design methodology. The system modeling methodology includes application model for capturing timing/power constraints and mode dependencies at the system level. The tool performs power-aware scheduling and mode selection to ensure that all timing/power constraints are satisfied and that all overhead is taken into account. IMPACCT then synthesizes the implementation targeting a symmetric multiprocessor platform. Experimental results show that the increased dynamic range of power/performance settings enabled a Mars rover to achieve significant acceleration while using less energy. More importantly, our tool correctly combines the state-of-the-art techniques at the system level, thereby saving even experienced designers from many pitfalls of system-level power management.