1. A server comprising: a plurality of processors, at least one of said processors being partitioned into a plurality of virtual partitions using a virtual partition hypervisor executed by said server, each of the plurality of virtual partitions using isolated hardware resources; wherein at least one of said plurality of virtual partitions is configured to execute a virtual machine hypervisor to implement a plurality of virtual machines within said at least one of said plurality of virtual partitions, in which the plurality of virtual machines share use of hardware resources allocated to said at least one of said virtual partitions; wherein said server is also configured to execute a workload manager application configured to: dynamically reallocate said processors among said plurality of virtual partitions responsive to measured processor utilization within said plurality of virtual partitions; analyze a measured utilization of processors in said plurality of virtual machines to determine if the processors allocated to the at least one of said virtual partitions are underutilized; and wherein said virtual partition hypervisor is configured to: based on said determination that said processors in said at least one of said plurality of virtual partitions are underutilized; migrate a superfluous processor from said at least one of said virtual partitions to said virtual partition hypervisor; and place said superfluous processor in a low power state; and wherein said virtual partition hypervisor and said virtual machine hypervisor are by nested heterogeneous hypervisors.