Performance prediction of N-body simulations on a hybrid architecture

Hybrid Architectures consist of Special Purpose Devices (SPD) used in conjunction with parallel computers. They have the potential of being a major computing tool for various applications of Computational Science. Mapping the application tasks to the hybrid machine is not trivial, and bottlenecks can arise quite easily. Performance Modeling is a suitable method to tackle this problem. The performance model presented here simulates the activity of GRAPE, a very powerful SPD used in Computational Astrophysics, in conjunction with a general purpose host. We show how our model faithfully reproduces the behaviour of the real hybrid machine. We also present some examples of how our model can be used to predict performance improvements.