Energy-aware Morphable Cache Management for Self-powered Non-volatile Processors

Wearable, implantable and Internet of Things devices are attracting increasing attention from both research and industry. Energy harvesting is a promising alternative of battery to power these embedded systems. However, the intrinsic instability of energy harvesting systems leads to potential frequent power interruptions. In order to survive the power failures, non-volatile processor (NVP) is proposed to back up volatile information before power depletion and recover the system status after power resumes. Non-volatile memory (NVM) is typically attached for cache and main memory backup. There are researches working on optimization of the backup, however, little of them involve multiple level cell (MLC) NVM. In this work, we first discuss the benefit of applying MLC NVM for cache backup, and then propose a three-stage energy-aware cache management strategy to improve the system performance and energy utilization while guaranteeing successful backups. Evaluation shows that the proposed scheme can achieve 16.7% energy reduction with comparative performance with the single level cell (SLC) based hybrid cache.