HyFlow: A High Performance Distributed Software Transactional Memory Framework

We present HyFlow - a distributed software transactional memory (D-STM) framework for distributed concurrency control. HyFlow is a Java framework for D-STM, with pluggable support for directory lookup protocols, transactional synchronization and recovery mechanisms, contention management policies, cache coherence protocols, and network communication protocols. HyFlow exports a simple distributed programming model that excludes locks: using (Java 5) annotations, atomic sections are defined as transactions, in which reads and writes to shared, local and remote objects appear to take effect instantaneously. No changes are needed to the underlying virtual machine or compiler. We describe HyFlow's architecture and implementation, and report on experimental studies comparing HyFlow against competing models including Java remote method invocation (RMI) with mutual exclusion and read/write locks, distributed shared memory (DSM), and directory-based D-STM. Our studies show that HyFlow outperforms competitors by as much as 40-190% on a broad range of transactional workloads on a 72-node system, with more than 500 concurrent transactions.