Abstract

We propose a new form of software transactional memory (STM) designed to support dynamic-sized data structures, and we describe a novel non-blocking implementation. The non-blocking property we consider is obstruction-freedom. Obstruction-freedom is weaker than lock-freedom; as a result, it admits substantially simpler and more e#cient implementations. A novel feature of our obstruction-free STM implementation is its use of modular contention managers to ensure progress in practice. We illustrate the utility of our dynamic STM with a straightforward implementation of an obstruction-free red-black tree, thereby demonstrating a sophisticated non-blocking dynamic data structure that would be di#cult to implement by other means. We also present the results of simple preliminary performance experiments that demonstrate that an "early release" feature of our STM is useful for reducing contention, and that our STM lends itself to the e#ective use of modular contention managers.

Citations