Abstract: A performance modeling tool and method permitting the user to define the elements of a distributed system (hosts, networks and response times), and examine the effect on performance of different distributions of application processes over the system at an early stage in application design. Once a user has defined a performance scenario, it is saved to a data model as a number of interdependent persistent objects that show the distribution of the application for a particular performance scenario from different views. Multiple alternates of each object can be stored. The user can construct different performance scenarios for analysis from the stored objects. Analysis can include performance simulation from which the user can obtain performance projections for an application process or several application processes over different distributions of the performance worload.