Simulation-based performance prediction for large parallel machines

We present a performance prediction environment for large scale computers such as the Blue Gene machine. It consists of a parallel simulator, BigSim, for predicting performance of machines with a very large number of processors, and BigNetSim, which incorporates a pluggable module of a detailed contention-based network model. The simulators provide the ability to make performance predictions for very large machines such as Blue Gene/L. We illustrate the utility of our simulators using validation and prediction studies of several applications using smaller numbers of processors for simulations.