Evaluation of the Cray XT3 at ORNL: a Status Report

Last year, Oak Ridge National Laboratory received delivery of a 5,294 processor Cray XT3. The XT3 is Cray’s third-generation massively parallel processing system. The system uses a single-processor node built around the AMD Opteron and uses a custom chip—called SeaStar—to provide interprocessor communication. In addition, the system uses a lightweight operating system on its compute nodes. This paper provides a status update since last year, including updated performance measurements for micro-benchmark, kernel, and application benchmarks. In particular, we provide performance results for strategic Department of Energy applications areas including climate, biology, astrophysics, combustion, and fusion. Our results, on up to 4096 processors, demonstrate that the Cray XT3 provides competitive processor performance, high interconnect bandwidth, and high parallel efficiency on a diverse application workload, typical in the DOE Office of Science.