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 processor temporary allocation being enabled in the logically partitioned data processing system, sending, by a temporarily allocating operating system on a dedicated logical partition, an indication to a virtual machine monitor that an idle dedicated processor is available for temporarily allocating to the shared processor pool, thereby forming an 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 an operating frequency of the identified dedicated processor is within a predetermined threshold of an operating frequency of one or more operating systems utilizing the shared processor pool; responsive to the operating frequency of the identified dedicated processor failing to be within the predetermined threshold of the operating frequency of the one or more operating systems utilizing the shared processor pool, either increasing or decreasing, by the virtual machine monitor, the frequency of the identified dedicated processor to be within the predetermined threshold of the 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.