Noninvasive concurrency with Java STM

In this paper we present a complete Java STM framework, called Deuce, intended as a platform for developing scalable concurrent applications and as a research tool for designing new STM algorithms. It was not clear if one could build an e cient Java STM without compiler support. Deuce provides several bene ts over existing Java STM frameworks: it avoids any changes or additions to the JVM, it does not require language extensions or intrusive APIs, and it does not impose any memory footprint or GC overhead. To support legacy libraries, Deuce dynamically instruments classes at load time and uses an original eld-based locking strategy to improve concurrency. Deuce also provides a simple internal API allowing di erent STMs algorithms to be plugged in. We show empirical results that highlight the scalability of our framework running benchmarks with hundreds of concurrent threads. This paper shows for the rst time that one can actually design a Java STM with reasonable performance without compiler support.