Effective Overlap of Computation with I/O Operations in Remote MPI-I/O Operations using a Multithreaded I/O Mechanism

Y. Tsujita (Japan)

Keywords

MPII/O, Stampi, MPII/O process, Multithreaded I/O

Abstract

A communication library named Stampi realizes MPI com munications among different computers, and it is supported in many kinds of parallel computers. In addition, I/O op erations based on the MPI-I/O APIs among different com puters are available with it. In remote I/O operations, MPI I/O processes are invoked on a remote computer to play I/O operations using a vendor-supplied MPI-I/O library. When the vendor-supplied one is not available on a re mote computer, a single MPI-I/O process is invoked, and it uses UNIX I/O functions instead of the vendor-supplied one. This may result in an increase in execution times for nonblocking MPI-I/O operations with an increase in the number of user processes. To make the times short, a Pthreads library has been introduced in an I/O mecha nism of the MPI-I/O process, and the newly implemented method makes the times short successfully. In this paper, details of the multithreaded MPI-I/O mechanism and pre liminary performance results are described.

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