An experimental evaluation of the parallel I/O systems of the IBM SP and Intel Paragon using a production application

Abstract

We present the results of an experimental evaluation of the parallel I/O systems of the IBM SP and Intel Paragon using a real three-dimensional parallel application code. This application, developed by scientists at the University of Chicago, simulates the gravitational collapse of self-gravitating gaseous clouds. It performs parallel I/O by using library routines that we developed and optimized separately for the SP and Paragon. The I/O routines perform two-phase I/O and use the parallel file systems PIOFS on the SP and PFS on the Paragon. We studied the I/O performance for two different sizes of the application. In the small case, we found that I/O was much faster on the SP. In the large case, open, close, and read operations were only slightly faster, and seeks were significantly faster, on the SP; whereas, writes were slightly faster on the Paragon. The communication required within our I/O routines was faster on the Paragon in both cases. The highest read bandwidth obtained was 48 Mbytes/sec., and the highest write bandwidth obtained was 31.6 Mbytes/sec., both on the SP.

This work was supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Computational and Technology Research, U.S. Department of Energy, under Contract W-31-109-Eng-38; and by the Scalable I/O Initiative, a multiagency project funded by the Advanced Research Projects Agency (contract number DABT63-94-C-0049), the Department of Energy, the National Aeronautics and Space Administration, and the National Science Foundation.