PSIM-a simulator for concurrent execution of net-based programs

We present a simulator for performance evaluation and visualisation of the execution of concurrent programs represented as nets. The notation for net description is based on Petri nets, augmented with semantic properties such as simultaneous firing of multiple transitions, finite firing time, and maturing of tokens in places. The flow of tokens in the net represents all possible flows of control among code segments, including parallelism, synchronisation and non-determinism. The simulator emulates parallel execution over a selectable number of processors; it accounts for hypothetical execution times of code segments, arbitrates conflicting transitions and randomises non-deterministic branches.