Performance Modeling of Deterministic Transport Computations

In this work we present a performance model that encompasses the key characteristics of a Sn transport application using unstructured meshes. Sn transport is an important part of the ASCI workload. This builds on previous analysis which has been done for the case of structured meshes. The performance modeling of an unstructured grid application presents a number of complexities and subtleties that do not arise for structured grids. The resulting analytical model is parametric using basic system performance characteristics (latency, bandwidth, MFLOPS rate etc), and application characteristics (mesh size etc). It is validated on a large HP AlphaServer system showing high accuracy. The model compares favorably to a trace based modeling approach which is specific to a single mesh/processor mapping situation. The model is used to give insight into the achievable performance on possible future processing systems containing thousands of processors.