1. A computer readable medium having stored thereon a plurality of instructions for determining an amount of a resource consumed during a simulation interval in a performance prediction simulation of a system, wherein the plurality of instructions, when executed by a processor, causes the processor to: calculate an aggregate resource requirement associated with the resource in a simulation interval; calculate a system event horizon for the simulation interval based on a resource usage state change in the system; and adjust the aggregate resource requirement based on the system event horizon to provide an adjusted aggregate resource requirement for the resource, wherein the adjusted aggregate resource requirement represents the amount of the resource consumed during the simulation interval; wherein the system includes a resource configuration, and the plurality of instructions further causes the processor to receive a resource topology tree defining the resource configuration of the system, wherein the resource is specified by the resource topology tree.