NAS Experience with the Cray X1

A Cray X1 computer system was installed at the NASA Advanced Supercomputing (NAS) facility at NASA Ames Research Center in 2004. An evaluation study of this unique high performance computing (HPC) architecture, from the standpoints of processor and system performance, ease of use, and production computing readiness tailored to the needs of the NAS scientific community, was recently completed. The results of this study are described in this article. The evaluation included system performance and characterization using a subset of the HPC Challenge benchmarks and NAS Parallel Benchmarks, as well as detailed performance on scientific applications from the computational fluid dynamics (CFD) and Earth science disciplines that represent a major portion of the computational workload at NAS. Performance results are discussed and compared with the main HPC platform at NAS — the SGI Altix.