Vcluster: A Portable Virtual Computing Library For Cluster Computing

Message passing has been the dominant parallel programming model in cluster computing, and libraries like Message Passing Interface (MPI) and Portable Virtual Machine (PVM) have proven their novelty and efficiency through numerous applications in diverse areas. However, as clusters of Symmetric Multi-Processor (SMP) and heterogeneous machines become popular, conventional message passing models must be adapted accordingly to support this new kind of clusters efficiently. In addition, Java programming language, with its features like object oriented architecture, platform independent bytecode, and native support for multithreading, makes it an alternative language for cluster computing. This research presents a new parallel programming model and a library called VCluster that implements this model on top of a Java Virtual Machine (JVM). The programming model is based on virtual migrating threads to support clusters of heterogeneous SMP machines efficiently. VCluster is implemented in 100% Java, utilizing the portability of Java to address the problems of heterogeneous machines. VCluster virtualizes computational and communication resources such as threads, computation states, and communication channels across multiple separate JVMs, which makes a mobile thread possible. Equipped with virtual migrating thread, it is feasible to balance the load of computing resources dynamically. Several large scale parallel applications have been developed using VCluster to compare the performance and usage of VCluster with other libraries. The results of the experiments show that VCluster makes it easier to develop multithreading parallel applications compared to conventional libraries like MPI. At the same time, the performance of VCluster is comparable to MPICH, a widely used MPI library, combined with popular threading libraries like POSIX Thread and OpenMP. In the next phase of our work, we implemented thread group and thread migration to demonstrate the feasibility of dynamic load balancing in VCluster. We carried out experiments to show that the load can be dynamically balanced in VCluster, resulting in a better performance. Thread group also makes it possible to implement collective communication functions between threads, which have been proved to be useful in process based libraries

Cluster Computing Environment Supporting Single System Image

Single system image(SSI) systems have been the mainstay of high-performance computing for many years. SSI requires the integration and aggregation of all types of resources in a cluster to present a single interface to users. In this paper, we describe a cluster computing environment supporting SSI, constructed through three components: single process space(SPS), process migration, and dynamic load balancing. These components attempt to share all available resources in the cluster among all executing processes, so that the cluster operates like a single node with much more computing power. The most important goal is to combine these constructs in innovative ways for building cluster computing environment for SSI, as well as individually take a novel approache to improve performance or functionality. Our implementation of process migration has the capability of resolving broken pipe problems and bind errors on server socket reconstruction. We realize SPS based on block PID allocation. We also designed and implemented a dynamic load balancing scheme which resolves the limitations of our previous work by continuously tracing the job resource usage at runtime. The experimental results show that these three constructs for SSI clusters realized scalability, new functionality and performance improvement. The cluster computing environment allows these constructs to cooperate implicitly so that they create a synergy effect at the SSI cluster system level and successfully provide a single system image to users and administrators.