A Study of In-Situ Visualization for Petascale Combustion Simulations

As scientific supercomputing moves toward petascale and exascale, in-situ visualization clearly becomes the most costeffective way to enable scientists see the full extent of the data generated by their simulations. This is particularly crucial for capturing and understanding highly intermittent transient phenomena, e.g. ignition/extinction events in turbulent combustion. However, integrating the visualization process into the simulation pipeline poses several challenges which have not been fully addressed. In this paper, we present a complete case study of in-situ visualization for a petascale combustion simulation. We describe our design decisions and optimization strategies on domain decomposition, rendering, and image compositing. We present an indepth evaluation of our implementation on the Cray XT5 at the NCCS/ORNL, and discuss the lessons learned through this study. We demonstrate that in-situ visualization is a feasible solution and our work provides a valuable guideline to those who will pursue a similar solution.