DONUTS: An efficient method for checkpointing in non‐volatile memories

Abstract

Non-volatile memory (NVM) is an emerging technology being explored as an alternative to DRAM main memory in computing systems because of its persistence, higher storage density, lower energy consumption, and access latency close to DRAM. However, persistent memory systems must ensure data consistency on system failures, a property known as crash consistency. One of the main challenges in these systems is creating efficient checkpointing mechanisms in terms of performance and usability. Thus, it is necessary to remove persistence from the critical execution path and reduce the excessive number of writes to NVM caused by logging operations, resulting in increased memory bandwidth usage. Another limitation is that most proposed mechanisms restrict application source code to programming interfaces based on transactional models, typed as software-based approaches. These factors make it challenging to adopt NVM systems. This article presents a software-transparent mechanism based on dynamic epochs with logging operations via processing-in-memory and checkpoints integrated into the cache replacement policy. Compared to the previous best-performing system, our strategy reduces 50.6% of writes to NVM. Furthermore, it does not increase the average memory bandwidth usage, providing crash consistency with less than 2% runtime overhead.