NVPsim: A simulator for architecture explorations of nonvolatile processors

Nonvolatile processors (NVPs) preserve run-time information when power failure occurs by utilizing nonvolatile memory technologies. This feature enables NVPs to make forward progress continuously under intermittent power supply in energy harvesting systems. This paper builds a gem5 based NVP simulator named NVPsim, which is validated against measured results of a fabricated prototype with reasonable error rate. Furthermore, to demonstrate the capability of NVPsim for architecture exploration, we evaluated performance and energy consumption of different NVP designs varying in the choice of nonvolatile memory for on-chip caches, the backup strategy and the energy buffer size. Experimental results indicate that nvSRAM outperforms other types of nonvolatile memory as the on-chip cache for energy harvesting systems.