| Object-based Collective Communication in Java |
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| Arnold Nelisse - Vrije Universiteit Thilo Kielmann - Vrije Universiteit Henri Bal - Vrije Universiteit Jason Maassen - Vrije Universiteit |
CCJ is a communication library that adds MPI-like collective operations to Java. Rather than trying to adhere to the precise MPI syntax, CCJ aims at a clean integration of collective communication into Java's object-oriented framework. For example, CCJ uses thread groups to support Java's multithreading model and it allows any data structure (not just arrays) to be communicated. CCJ is implemented entirely in Java, on top of RMI, so it can be used with any Java virtual machine. The paper discusses three parallel Java applications that use collective communication. It compares the performance (on top of a Myrinet cluster) of CCJ, RMI and mpiJava versions of these applications, and also compares the code complexity of the CCJ and RMI versions. The results show that the CCJ versions are significantly simpler than the RMI versions and obtain a good performance. |