The increasing complexity and software content of embedded systems has led to the frequent use of system software that helps applications access underlying hardware resources easily and efficiently. In this paper, we analyze the power consumption of real-time operating systems (RTOSs), which form an important component of the system software layer. Despite the widespread use of, and significant role played by, RTOSs in mobile and low-power embedded systems, little is known about their power consumption characteristics. This work presents the power profiles for a commercial RTOS, muC/OS, running several applications on an embedded system based on the Fujitsu SPARClite processor. Our work demonstrates that the RTOS can consume a significant fraction of the system power and, in addition, impact the power consumed by other software components. We illustrate the ways in which application software can be designed to use the RTOS in a power-efficient manner. We believe that this work is a first step towards establishing a systematic approach to RTOS power modeling and optimization.
