1. A virtualization management system comprising: a database that includes a plurality of multi-variate overhead profiles corresponding to amounts of overhead associated with running tasks on one or more virtual machines on one or more measured computer systems, an input element that is configured to receive an allocation of target virtual machines among one or more target computer systems, and an assignment of tasks to each of the target virtual machines, a selector element that is configured to select one or more target profiles of the plurality of overhead profiles corresponding to the one or more target computer systems, a performance modeling engine that is configured to estimate an overhead measure associated with each target computer system based on the one or more target profiles, the allocation of virtual machines to the target computer system, and the assignment of tasks to each of the target virtual machines, and an output element that is configured to provide the overhead measure associated with each target computer system.