Interconnection Network Simulation Using Traces of MPI Applications

This paper addresses the utilization of traces taken from MPI applications to do simulation-based performance studies of parallel computing systems. Different mechanisms to capture traces are discussed, pointing out important limitations of some of them. One of these limitations is the invisibility of message interchanges in collective operations, which is circumvented modifying a trace-capturing library. During a simulation, trace records must be simulated in causal order, to fully comply with application semantics. Alternatives to follow this order, and the risks of not following it, are presented and discussed. The techniques introduced in this paper have been implemented in an in-house developed simulation environment, which is used in two example studies to show its usefulness: an evaluation of alternatives for interconnection network design, and a performance prediction study in which traces from one machine are used to estimate the execution times of applications running in a different machine.