Cluster Computing

, Volume 11, Issue 1, pp 75–90

A framework for characterizing overlap of communication and computation in parallel applications

Authors

    • The Ohio State University
  • P. Sadayappan
    • The Ohio State University
  • David E. Bernholdt
    • Oak Ridge National Laboratory
  • Jarek Nieplocha
    • Pacific Northwest National Laboratory
  • Vinod Tipparaju
    • Pacific Northwest National Laboratory
Article

DOI: 10.1007/s10586-007-0046-3

Cite this article as:
Shet, A.G., Sadayappan, P., Bernholdt, D.E. et al. Cluster Comput (2008) 11: 75. doi:10.1007/s10586-007-0046-3

Abstract

Effective overlap of computation and communication is a well understood technique for latency hiding and can yield significant performance gains for applications on high-end computers. In this paper, we propose an instrumentation framework for message-passing systems to characterize the degree of overlap of communication with computation in the execution of parallel applications. The inability to obtain precise time-stamps for pertinent communication events is a significant problem, and is addressed by generation of minimum and maximum bounds on achieved overlap. The overlap measures can aid application developers and system designers in investigating scalability issues. The approach has been used to instrument two MPI implementations as well as the ARMCI system. The implementation resides entirely within the communication library and thus integrates well with existing approaches that operate outside the library. The utility of the framework is demonstrated by analyzing communication-computation overlap for micro-benchmarks and the NAS benchmarks, and the insights obtained are used to modify the NAS SP benchmark, resulting in improved overlap.

Keywords

Communication-computation overlap Latency hiding Performance instrumentation and monitoring Parallel applications

Copyright information

© Springer Science+Business Media, LLC 2008