Message Passing: A Case for Mixing Deep-Copy and Migration

Overview & Synopsis

This paper proposes an ownership model that permits to combine both a deep-copy and migration semantics within one consistent message-oriented programming model for Java. We argue that both semantics are necessary to cover the complete spectrum of application patterns. We also argue that one memory isolation mechanism is enough to provide strict memory isolation (isolate style) and message-oriented isolation suited for concurrent programming (actor style). Our proposal combines strict memory isolation, modeled on Java isolates (JSR 121),and a message passing that can send unconstrained object graphs, either migrating or deep-copying them. To our knowledge, our ownership model is the only model that does not specialize classes for their use in messages and still enables fast migration of unconstrained object graphs. Our performances show that the technology is suitable for interpreted virtual machines and are strong evidence that it is also suited for high-performance virtual machine based on JIT compilation.