• Software Scalability (Tuesday 10:30AM-Noon)
    Room A102/104/106
    Chair: Klaus Schauser, University of California, Santa Barbara

    • Title: Scalable Parallel Application Launch on Cplant
    • Authors:
      Ron Brightwell (Sandia National Laboratories)
      Lee Ann Fisk (Sandia National Laboratories)
    • Abstract:
      This paper describes the components of a runtime system for launching parallel applications and presents performance results for starting a job on more than a thousand nodes of a workstation cluster. This runtime system was developed at Sandia National Laboratories as part of the Computational Plant (Cplant) project, which is deploying large-scale parallel computing clusters using commodity hardware and the Linux operating system. We have designed and implemented a flexible runtime system that allows for launching parallel jobs on thousands of nodes in a matter of seconds. The interactions of the components are described, and the key issues that address the scalability and performance of the runtime system are discussed. We also present performance results of launching executables of varying sizes on more than a thousand nodes.

    • Title: Scaling Irregular Parallel Codes with Minimal Programming Effort
    • Authors:
      Dimitrios S. Nikolopoulos (University of Illinois at Urbana-Champaign)
      Constantine D. Polychronopoulos (University of Illinois at Urbana-Champaign)
      Eduard Ayguade (Universitat Politecnica de Catalunya)
    • Abstract:
      The long foreseen goal of parallel programming models is to scale parallel code without significant programming effort. Irregular parallel applications are a particularly challenging application domain for parallel programming models, since they require domain specific data distribution and load balancing algorithms. From a performance perspective, shared-memory models still fall short of scaling as well as message-passing models in irregular applications, although they require less coding effort. We present a simple runtime methodology for scaling irregular applications parallelized with the standard OpenMP interface. We claim that our parallelization methodology requires the minimum amount of effort from the programmer and prove experimentally that it is able to scale two highly irregular codes as well as MPI, with an order of magnitude less programming effort. This is probably the first time such a result is obtained from OpenMP, more so, by keeping the OpenMP API intact.

    • Title: A Parallel Java Grande Benchmark Suite
    • Authors:
      L. A. Smith (EPCC, University of Edinburgh)
      J. M. Bull (EPCC, University of Edinburgh)
      J. Obdrzalek (Faculty of Informatics, Masaryk University)
    • Abstract:
      Increasing interest is being shown in the use of Java for large scale or Grande applications. This new use of Java places specific demands on the Java execution environments that can be tested using the Java Grande benchmark suite. The large processing requirements of Grande applications makes parallelisation of interest. A suite of parallel benchmarks has been developed from the serial Java Grande benchmark suite, using three parallel programming models: Java native threads, MPJ (a message passing interface) and JOMP (a set of OpenMP-like directives). The contents of the suite are described, and results presented for a number of platforms.