Energy simulation of embedded XScale systems with XEEMU

Energy efficiency is key in embedded system design. Understanding the complex issue of software power consumption in early design phases is of extreme importance to make the right design decisions. Here, not only the CPU but also the external memory plays a very important role. Power simulators offer flexibility and allow a detailed view on the sources of power consumption. However, many simulators lack accuracy and focus only on the CPU core without considering the memory subsystem. In this paper, we present XEEMU, a fast, cycle-accurate simulator, which aims at accurately simulating the power consumption of an XScale-based system including its memory subsystem. It has been validated using measurements on real hardware and shows a high accuracy for runtime, instantaneous power, and total energy consumption estimation. The average error is as low as 3.0% and 1.6% for runtime and CPU energy consumption estimation, respectively.