Lightweight Transparent Java Thread Migration for Distributed JVM

A distributed JVM on a cluster can provide a highperformance platform for running multi-threaded Java applications transparently. Efficient scheduling of Java threads among cluster nodes in a distributed JVM is desired for maintaining a balanced system workload so that the application can achieve maximum speedup. We present a transparent thread migration system that is able to support high-performance native execution of multi-threaded Java programs. To achieve migration transparency, we perform dynamic native code instrumentation inside the JIT compiler. The mechanism has been successfully implemented and integrated in JESSICA2, a JIT-enabled distributed JVM, to enable automatic thread distribution and dynamic load balancing in a cluster environment. We discuss issues related to supporting transparent Java thread migration in a JIT-enabled distributed JVM, and compare our solution with previous approaches that use static bytecode instrumentation and JVMDI. We also propose optimizations including dynamic register patching and pseudo-inlining that can reduce the runtime overhead incurred in a migration act. We use measured experimental results to show that our system is efficient and lightweight.