The purpose of this article is to design a controller, which guarantees a structural specification while increasing a performance measure. The system which is to be controlled is modelled by a Petri net and the supervisory controller is constructed in the form of a set of routing functions. If the system is controllable, the solution of the evolution equations gives a feasible region for the routing parameters for places with several output transitions. Any point in that feasible region corresponds to a set of values for which the structural specification is guaranteed. We propose a heuristic method which searches the feasible region to find the routing parameters that increase the throughput of the system. The advantages of the approach is two-fold: 1. the fulfilment of two specifications which are different in nature are handled together; 2. in general, the timed model of a system is used for the performance analysis of a system. Here, the evolution equations obtained by using routing functions are based on the un-timed interpretation of the Petri net. || Dans cet article, on montre comment obtenir un contrôleur discret qui garantit une spécification structurelle (ici l'absence de famine) et une autre de type performance (ici l'augmentation du débit). Le problème posé a été résolu dans le cadre d'un modèle