1. A method, in a data processing system, for controlling a fidelity of a simulation of a system, comprising: receiving a model of the system, wherein the model of the system comprises a plurality of individual components of the system; assigning fidelity values to models of the individual components of the system; executing a simulation of the system using the model of the system and the models of the individual components of the system; determining, for each component in the plurality of individual components of the system, an activity level of the component during execution of the simulation; and dynamically adjusting fidelity values of one or more of the models of the individual components of the system during the execution of the simulation based on changes in individual activity levels of the individual components.