Brief Announcement: Persistent Multi-Word Compare-and-Swap

This brief announcement presents a fundamental concurrent primitive for persistent memory - a persistent atomic multi-word compare-and-swap (PMCAS). We present a novel algorithm carefully crafted to ensure that atomic updates to a multitude of words modified by the PMCAS are persisted correctly. Our algorithm leverages hardware transactional memory (HTM) for concurrency control, and has a total of 3 persist barriers in its critical path. We also overview variants based on just the compare-and-swap (CAS) instruction and a hybrid of CAS and HTM.