Component based system (CBS) development is now a well accepted design approach in software engineering. Although specific tools used for building CBS perform several checks on the built system, few of them provide formal verification of behavioural properties nor performance evaluation. In this context, we have developed a general method associating to a CBS a formal model, based on Stochastic Well formed Nets, a class of high level Petri Nets, allowing qualitative behavioural analysis and performance evaluation of the CBS. The definition of the model heavily depends on the (run time) component model used to describe the CBS. In this paper, we apply our method to Fractal CBS and its reference Java implementation Julia, concentrating on performance evaluation. The main interest of our method is to take advantage of the compositional definition of such systems to carry out an efficient analysis, starting from the Fractal architectural description of a CBS.