1. A method for constructing a model useful for predicting performance of a system that includes a plurality of interconnected components defining at least one data flow path, the method comprising: referencing a workload specification for the system; and modeling the system using one or more component models, each component model representing selected one or more of the components, each component model arranged in like relationship to the data flow path as the selected one or more of the components represented by the component model, wherein each component model comprises (a) a constraint upon the workload specification input to that component model or (b) a transformer of the workload specification input to that component model so as to result in one or more output workloads that are input workload specifications to subsequent component models along the data flow path or (c) both a constraint and a transformer, and wherein at least one of the component models comprises a constraint.