Nowadays, software have to be efficient, fast to execute, etc. They can be configured to adapt to specific needs. Each configuration leads to a different system and usually it is hard to generate them all. Thus, the exhaustive evaluation of their performance is impossible. Furthermore, several executions of systems, under different conditions, are needed to properly evaluate performances. Two dimensions emerge from this description of performance testing: the selection of system configurations allowing to generate associated systems that meet expressed needs and the selection of test cases allowing to observe performances of systems under different conditions. We propose to represent those two dimensions as a (performance) matrix: one dimen...