Parallel execution for serial simulators

This article describes an approach to discrete event simulation modeling that appears to be effective for developing portable and efficient parallel execution of models of large distributed systems and communication networks. In this approach, the modeler develops submodels with an existing sequential simulation modeling tool, using the full expressive power of the tool. A set of modeling language extensions permits automatically synchronized communication between submodels; however, the automation requires that any such communication must take a nonzero amount of simulation time. Within this modeling paradigm, a variety of conservative synchronization protocols can transparently support conservative execution of submodels on potentially different processors. A specific implementation of this approach, U.P.S. (Utilitarian Parallel Simulator), is described, along with performance results on the Intel Paragon and on the IBM SP2.