Implementing the NHT-1 Application I/O Benchmark

Implementing the NHT-1 Application I/O
Benchmark
Samuel A. Fineberg
Report RND-93-007 May 1993
1Computer Sciences Corporation
Numerical Aerodynamic Simulation
NASA Ames Research Center, M/S 258-6
Moffett Field, CA 94035-1000
(415)604-4319
e-mail: fineberg@nas.nasa.gov
Abstract
The NHT-1 I/O (Input/Output) benchmarks are a benchmark suite developed at the
Numerical Aerodynamic Simulation Facility (NAS) located at NASA Ames
Research Center. These benchmarks are designed to test various aspects of the I/O
performance of parallel supercomputers. One of these benchmarks, the Applica-
tion I/O Benchmark, is designed to test the I/O performance of a system while exe-
cuting a typical computational fluid dynamics application. In this paper, the
implementation of this benchmark on three parallel systems located at NAS and
the results obtained from these implementations are reported. The machines used
were an 8 processor Cray Y-MP, a 32768 processor CM-2, and a 128 processor
iPSC/860. The results show that the Y-MP is the fastest machine and has relatively
well balanced I/O performance. I/O adds 2-40% overhead, depending on the num-
ber of processors utilized. The CM-2 is the slowest machine, but it has I/O that is
fast relative to its computational performance. This resulted in typical I/O over-
heads on the CM-2 of less than 4%. Finally, the iPSC/860, while not as computa-
tionally fast as the Y-MP, is considerably faster than the CM-2. However, the
iPSC/860’s I/O performance is ...