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The Message Passing Interface (MPI) is a software platform that can utilize the parallel capabilities of most multi-processors, making it useful for teaching students about parallel and distributed computing (PDC). MPI provides language bindings for Fortran and C/C++, but many university instructors lack expertise in these languages, preventing them from using MPI in their courses. OpenMPI is a free implementation of MPI that also provides Java bindings, allowing instructors who know Java but not C/C++ or Fortran to teach PDC. However, Java has a reputation as a “slow” language, so some say it is unsuitable for teaching PDC. This paper gives a head-to-head comparison of the performance of OpenMPI's Java and C bindings. Our study shows that by default, Java can be faster than C unless one takes special measures, and it exhibits similar speedup, efficiency, and scalability. We conclude that Java is a suitable language for teaching PDC.
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Using Software-Based Performance Counters to Expose Low-Level Open MPI Performance Information
This paper details the implementation and usage of software-based performance counters to understand the performance of a particular implementation of the MPI standard, Open MPI. Such counters can expose intrinsic features of the software stack that are not available otherwise in a generic and portable way. The PMPI-interface is useful for instrumenting MPI applications at a user level, however it is insufficient for providing meaningful internal MPI performance details. While the Peruse interface provides more detailed information on state changes within Open MPI, it has not seen widespread adoption. We introduce a simple low-level approach that instruments the Open MPI code at key locations to provide fine-grained MPI performance metrics. We evaluate the overhead associated with adding these counters to Open MPI as well as their use in determining bottlenecks and areas for improvement both in user code and the MPI implementation itself.
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- Award ID(s):
- 1664142
- PAR ID:
- 10062121
- Date Published:
- Journal Name:
- EuroMPI
- Page Range / eLocation ID:
- 1 to 8
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1145/3127024.3127039
