According to one embodiment, a processor includes a plurality of processor cores to execute a plurality of threads, a shared memory that is communicatively coupled to the plurality of processor cores, a power control unit (PCU) that is communicatively coupled to the plurality of processors, for determining , without any intervention of software (SW), whether a thread that is being performed by a first processor core, should be migrated to a second processor core, and a migration unit for, in response to receiving a command from the PCU, migrating the thread in that the second processor core executing the thread on the basis of the architecture state shared at least a portion of the architectural state of the first processor core for storage in shared memory and to migrate the thread to the second processor core, without any intervention of SW, so from the memory without Wiss s SW can proceed.