MPI Derived Datatypes
Qingqing Xiong, Purushotham Bangalore, Anthony Skjellum, Martin Herbordt · 2018
This paper addresses performance-portability and overall performance issues when derived datatypes are used with four MPI implementations: Open MPI, MPICH, MVAPICH2, and Intel MPI. These comparisons are particularly relevant today since most vendor implementations are now based on Open MPI or MPICH rather than on vendor proprietary code as was more prevalent in the past. Our findings are that, within a single MPI implementation, there are significant differences in performance as a function of it reasonable encodings of derived datatypes as supported by the MPI standard. While this finding may not be surprising, it is important to understand how fundamental vs. arbitrary choices made in early implementation impact the use of derived datatypes to date.