No abstract

Blue Gene/L uses a large number of low power processors, together with multiple integrated interconnection networks, to build a supercomputer with low cost, space and power consumption. It uses a novel system software architecture designed with application scalability in mind. However, whether real applications will scale to tens of thousands of processors has been an open question. In this paper, we describe early experience with several applications on a 16,384 node Blue Gene/L system. This study establishes that applications from a broad variety of scientific disciplines can effectively scale to thousands of processors. The results reported in this study represent the highest performance ever demonstrated for most of these applications, and in fact, show effective scaling for the first time ever on thousands of processors.

The High Order Method Modeling Environment is a scalable, spectral-element-based prototype for the Community Atmospheric Model component of the Community Climate System Model. The 3D moist primitive equations are solved on the cubed sphere with a hybrid pressure η vertical coordinate using an Emanuel convective parametrization for moist processes. Semi-implicit time integration, based on a preconditioned conjugate gradient solver, circumvents the time step restrictions associated with gravity waves. Benchmarks for two standard tests problems at 10 km horizontal resolution have been run on Blue Gene/L. Results obtained on a 32-rack Blue Gene/L system (65,536 processors, 183.5-teraflop peak) show sustained performance of 8.0 teraflops on 32,768 processors for the moist Held–Suarez test problem in coprocessor mode and 11.3 teraflops on 32,768 processors for the aquaplanet test problem, running in virtual node mode.