Energy leakage in low power embedded operating systems using DVFS policy

The leakage energy consumption is substantial and increasing for multiprocessor systems. That is why embedded operating systems adapt power management decisions to the variable characteristics of cores, improving system-wide power consumption and performance. Low power operating systems use key techniques such as Dynamic Voltage Frequency Scaling (DVFS) to save the energy consumption by changing dynamically the supply voltage and operating frequency. When the processor changes the execution from one task to another or vary the core frequency, an amount of energy is consumed. We, in this paper, propose an approach that characterizes the overhead of context switch in low power embedded operating systems. We study the influence of hardware and software parameters on the energy consumption. Then, we extract models of the energy overhead. We apply the proposed approach to multi-process software benchmark programs and we validate its applicability in the context of an embedded system containing an OMAP3530 processor and running embedded Linux as an operating system.