Java-Based DSM with Object-Level Coherence Protocol Selection

This paper describes a Java-based distributed shared memory system (DSM) that simultaneously supports multiple coherence protocols. Coherence is enforced at the object level, and programmers can select the desired policy at object-creation time. Our work extends the Aleph Toolkit [1], a framework for distributed computing in Java. Since Aleph and our extensions are written in pure Java, the system is completely portable and can leverage immediately off of future improvements in the JDK. We demonstrate that a multiple-writer protocol that we added to the Toolkit outperforms existing Aleph protocols for some applications, and that a combination of protocols can provide performance superior to that resulting from the use of a single coherence scheme.