Energy driven application self-adaptation at run-time

Until recently, there has been a lack of methods to trade-off energy use for quality of service at run-time in stand-alone embedded systems. Such systems are motivated by the need to increase the apparent available battery energy of portable devices, with minimal compromise in quality. The available systems either drew too much power or added considerable overheads due to task swapping. In this paper we demonstrate a feasible method to perform these trade-offs. This work has been enabled by a low-impact power/energy estimating processor which utilizes counters to estimate power and energy consumption at run-time. Techniques are shown that modify multimedia applications to differ the fidelity, of their output to optimize the energy/quality trade-off. Two adaptation algorithms are applied to multimedia applications demonstrating the efficacy of the method. The method increases code size by 1% and execution time by 0.02%, yet is able to produce an output which is acceptable and processes up to double the number of frames.