Energy modeling of the virtual memory subsystem for real-time embedded systems

While operating systems are now largely used in embedded system design, their energy consumption is far from negligible. Being able to determine the part of this consumption in the system's overall energy budget is therefore essential. This paper proposes a methodology to model the power and energy consumption of virtual memory management mechanisms in complex operating systems. Of course, this work is only a part of a bigger project in which all the consuming components in embedded systems are considered. The virtual memory subsystem of a complete and recent Linux (patched for real-time) is studied here, with its relation with the processor's memory management ressources (Memory Management Unit and Translation Look-aside Buffer). A method is proposed to generate different categories of page faults, and to model the incurred time and energy penalties for different page allocation strategies. The precision of the model is presented, and finally checked against actual measurements for an image processing application.