Multiversioned Page Overlays: Enabling Faster Serializable Hardware Transactional Memory

Practical and efficient support for multiversioning memory systems would offer a number of potential advantages, including improving the performance and functionality of hardware transactional memory (HTM). This paper presents a new approach to multiversioning support (Multiversioned Page Overlays) along with a new HTM design that it enables: OverlayTM. Compared with existing HTM designs, OverlayTM takes advantage of multiversioning to reduce unnecessary transaction aborts while providing full serializable semantics (in contrast with multiversioning HTMs that improve performance at the expense of being vulnerable to write skew anomalies). Our performance results demonstrate that OverlayTM is especially advantageous in read-heavy workloads.