Title

Modelling parallel overhead from simple run-time records

Authors

Siegfried Höfinger, Michigan Technological UniversityFollow
Ernst Haunschmid, Technische Universitat Wien

Document Type

Article

Publication Date

10-2017

Department

Department of Physics

Abstract

A number of scientific applications run on current HPC systems would benefit from an approximate assessment of parallel overhead. In many instances a quick and simple method to obtain a general overview on the subject is regarded useful auxiliary information by the routine HPC user. Here we present such a method using just execution times for increasing numbers of parallel processing cores. We start out with several common scientific applications and measure the fraction of time spent in MPI communication. Forming the ratio of MPI time to overall execution time we obtain a smooth curve that can be parameterized by only two constants. We then use this two-parameter expression and extend Amdahl’s theorem with a new term representing parallel overhead in general. Fitting the original data set with this extended Amdahl expression yields an estimate for the parallel overhead closely matching the MPI time determined previously.

Publisher's Statement

© 2017, The Author(s). Publisher’s version of record: https://doi.org/10.1007/s11227-017-2023-9

Publication Title

Journal of Supercomputing

Recommended Citation

Höfinger, S., & Haunschmid, E. (2017). Modelling parallel overhead from simple run-time records. Journal of Supercomputing, 73(10), 4390-4406. http://doi.org/10.1007/s11227-017-2023-9
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/5013

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Version

Publisher's PDF