@TechReport{sanders:datatypes, author = {Darren Sanders and Yoonho Park and Maciej Brodowicz}, title = {Implementation and performance of {MPI-IO} file access using {MPI} datatypes}, year = {1996}, month = {November}, number = {UH-CS-96-12}, institution = {University of Houston}, URL = {http://www.hpc.uh.edu/cenju/pub/mpio.ps}, keywords = {parallel I/O, multiprocessor file system interface, pario-bib}, abstract = {In this paper we document our experience implementing MPI-IO file access using MPI datatypes. We present performance results and discuss two significant problems that stem from the flexibility of MPI datatypes. First, MPI datatypes can be used to specify non-contiguous access patterns. Optimizing data transfers for such patterns is difficult. Second, the behavior of MPI datatypes in a heterogenous environment is not well-defined.}, comment = {They devise several file-access strategies for different situations, depending on the particulars of the etypes and filetypes in use: sequential, two-phase I/O, one file access per etype (random access), and one file access per etype element (random access with smaller pieces). They measure the performance of their system with example patterns that trigger each strategy. It would be nice to see a more extensive performance analysis of their implementation, and of their strategies.} }