Modeling concurrent programs with colored Petri nets

Abstract

We show how colored Petri nets can be used to model concurrent programs. We describe a translation from a substantive subset of Ada including dynamic tasking, subroutines, and generics, constructs that have not been modeled with Petri nets before. The technical challenge overcome by translation is to avoid duplicated subnets in the presence of synchronization. This assists modular analysis of the components. The translation has been implemented in the programming language ML. We develop a new Petri net model for concurrent programs using colored Petri nets. This model is concise, natural, and has other properties desirable for the purposes we require. The model uses a relatively rare form of colored Petri nets to achieve these advantages. We describe some techniques we have developed to analyze the colored Petri net model. In particular, we consider a notion of a critical path in the model. We apply these techniques to models of Ada programs.