A Region-Based Approach to Pipeline Parallelism in Java Programs on Multicores

As multicore architectures dominate mainstream computing platforms, migrating legacy applications into their parallel representation becomes a viable approach to reaping the benefits of multicore computing. In this paper we present a dataflow analysis tool that assists programmers to exploit the coarse-grained pipeline parallelism in stream-like Java applications on multicores. With this tool, programmers can partition a source Java program into a set of regions, which as pipeline stages, are connected via data channels to execute on multicores. To this end, we propose a simple yet effective framework that leverages JVMTI (JVM Tool Interface) and Java agent techniques to track the data communication patterns among different regions, whereby a stream graph of the program is constructed. The graph is further used by the framework and programmers to re-factor the Java application into a pipelined program so that the potential of the multicores can be fully utilized. This procedure can be repeated in several rounds to progressively improve the performance. By applying this tool to several selected benchmarks, we demonstrate the effectiveness of the approach in terms of the performance improvements of some stream-like Java applications.