Performance predictions for a numerical relativity package in grid environments

The Cactus software package is representative for a class of scientific app lications that are tightly coupled, have regular space decompositions, and involve huge memory and processor time requirements. Cactus has proved to b e a valuable tool for astrophysicists, who first initiated its development. However, today's fastest supercomputers are not powerful enough to perform realistic large-scale astrophysics simulations with Cactus. Instead, astro physicists must turn to innovative resource environments-in particular, com putational grids-to satisfy this need for computational power. This paper a ddresses issues related to the execution of applications such as Cactus in grid environments. The authors focus on two types of grids: a set of geogra phically distributed supercomputers and a collection of one million Interne t-connected workstations. The authors study the application performance on traditional systems, validate the theoretical results against experimental data, and predict performance in the two new environments.