On Developing Optimistic Transactional Lazy Set

Transactional data structures with the same performance of highly concurrent data structures enable performance-competitive transactional applications. Although Software Transactional Memory (STM) is a promising technology for designing and implementing transactional applications, STM-based transactional data structures still perform inferior to their optimized, concurrent (i.e. non-transactional) counterparts. In this paper, we present OTB-Set, an efficient optimistic transactional lazy set based on both linked-list and skip-list implementations. We first provide general guidelines to show how to design a transactional (non-optimized) version of the highly concurrent lazy set with a minimal reengineering effort. Subsequently, we show how to make specific optimizations to the implementations of the OTB-Set for further enhancing its performance. We also prove that our OTB-Set provides linearizable individual operations and opaque transactions. Our experimental study on a 64-core machine reveals that OTB-Set outperforms competitors in most workloads.