1. A method for managing a contended computer system resource comprising: measuring an aggregated resource performance metric; for each of a selected plurality of clients, determining a client performance metric; for each of the selected plurality of clients, determining a relationship measure as a function of the aggregated resource performance metric and the respective client performance metric; determining a degree of resource contention effect for each of the selected plurality of clients as a function of the respective relationship measure; and taking a resource-related action according to the respective relationship measures; in which: the relationship measure is a function of correlation between the aggregated resource performance metric and each respective client performance metric; and the resource-related action includes adjusting allocation of the contended resource among the clients.