1. A method, in a logically partitioned data processing system, for temporarily allocating one or more dedicated processors to a shared processor pool, the method comprising: responsive to a dedicated logical partition in the logically partitioned data processing system being enabled to temporarily allocate one or more dedicated processors, sending, by a temporarily allocating operating system on the dedicated logical partition, an indication to a virtual machine monitor that an idle dedicated processor is available for temporary allocation to the shared processor pool, thereby forming all identified dedicated processor; determining, by the virtual machine monitor, whether the temporary allocation associated with the identified dedicated processor is long-term or short-term; responsive to the temporary allocation being long-term: determining, by the virtual machine monitor, whether a current-running operating frequency of the identified dedicated processor is within a predetermined threshold of a current-running operating frequency of one or more operating system utilizing the shared processor pool; responsive to the current-running operating frequency of the identified dedicated processor failing to be within the predetermined threshold of the current-running operating frequency of the one or more operating systems utilizing the shared processor pool, either increasing or decreasing, by the virtual machine monitor, an operating frequency of the identified dedicated processor to be within the predetermined threshold of the current-running operating frequency of the one or more operating systems utilizing the shared processor pool; and allocating, by the virtual machine monitor, the identified dedicated processor to the shared processor pool; and responsive to the temporary allocation being short-term: determining, by the virtual machine monitor, whether the current-running operating frequency of the identified dedicated processor is within the predetermined threshold of the current-running operating frequency of the one or more operating systems utilizing the shared processor pool; and responsive to the current-running operating frequency of the identified dedicated processor being within the predetermined threshold of the current-running operating frequency of the one or more operating systems utilizing the shared processor pool, allocating, by the virtual machine monitor, the identified dedicated processor to the shared processor pool.