A performance manager and method for managing the performance of a computer system based on a system model that includes measured entities representing the operational characteristics of the system components and relationships among the measured entities. The performance manager includes data producers for interacting with the interface agents of the components, an engine for exchanging information with the data producers and the system model, and an interaction model for determining relevant measured entities in the system model. The system model and interaction model are maintained in a repository where data might be accessed via an access interface. Incoming performance data is analyzed by an analyzer in the background to detect trends and relationships among the entities. An operator might review the relevant entities and apply controls to selected entities to manage the overall system performance as well as to resolve problems affecting the performance of the components in the system.