Scheduling Distributed Applications: the SimGrid Simulation Framework

Since the advent of distributed computer systems an active field of research has been the investigation of scheduling strategies for parallel applications. The common approach is to employ scheduling heuristics that approximate an optimal schedule. Unfortunately, it is not possible to obtain analytical results to compare and select appropriate heuristics for a given scheduling problem. One possibility is to conducts large numbers of back-to-back experiments on real platforms. While this is possible on tightly-coupled platforms, it is infeasible on modern distributed platforms such as the Computational Grid as it is labor-intensive and does not enable repeatable results. The solution is to resort to simulations. Simulations not only lead to repeatable results but also make it possible to explore wide ranges of platform and application scenarios. In this paper we present the SimGrid framework which enables the simulation of distributed applications in distributed computing environments for the specific purpose of developing and evaluating scheduling algorithms. This paper focuses on SimGrid v2, which greatly improves on the first version of the software. Enhancements include improved and more realistic network models, as well as means to import platform simulation models from platform monitoring tools. SimGrid v2 also enables the simulation of distributed scheduling agents, which has become critical for current scheduling research in the area of Grid computing. After describing and validating these features, we present a case study by which we demonstrate the usefulness of SimGrid for conducting scheduling research.