Redesigning software and systems for nonvolatile processors on self-powered devices

Wearable devices gain increasing popularity since they can collect important information for healthcare and well-being purposes. Compared with battery, energy harvesting is a better power source for these wearable devices due to many advantages. However, harvested energy is naturally unstable and program execution will be interrupted frequently with harvested energy supply. Nonvolatile processor (NVP) demonstrates promising advantages to back up volatile state before the system energy is depleted and resume the processor status so that the program execution can be accumulative with power failures. Due to the backup and resumption procedures resulting from power failures, nonvolatile processor exhibits significantly different characteristics from traditional processors, necessitating a set of adaptive design and optimization strategies. Recently, there have been both hardware and software researches aiming to develop correct and efficient nonvolatile processors. In this paper, we summarize recently proposed software-level techniques for NVP, covering error-correctness schemes, backup timing determination, backup content optimization, adaptive software modifications, and NVP simulators and tools, to provide an overview of state-of-the-art NVP research from the software and system level.