A Performance Model of Direct Numerical Simulation for Analyzing Large-Scale Systems

In this work we develop, validate and use a performance model of the combustion code DNS3D that uses Direct Numerical Simulation to model turbulence in fluid motion. This is an important application area and is expected to use large fractions of future large-scale systems. From a thorough analysis of the code, its key computational characteristics are coupled with the performance characteristics of a parallel system using an analytical performance model that is parameterized in terms of key application and system aspects. The performance model is validated on two current systems, a multi-core AMD Opteron system with an Infiniband interconnect, and an IBM Power5+ system with an HPS interconnect. High prediction accuracies are demonstrated on these two systems. The model can be used to explore changes in the performance characteristics of either the application or of the systems, and in particular to examine the processing possibilities for DNS3D on future systems. We illustrate here how the model can be used to explore the impact of changes in the characteristics of either the system or of the application.