Аннотация: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 Application I/O Benchmark, is designed to test the I/O performance of a system while executing 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 number 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 overheads on the CM-2 of less than 4%. Finally, the iPSC/860, while not as computationally fast as the Y-MP, is considerably faster than the CM-2. However, the iPSCI860's I/O performance is quite poor and can add overhead of more than 70%.
