Abstract: The present invention relates to a method and apparatus of lock transactions processing in a single or multi-core processor. An embodiment of the present invention is a processor with one or more processing cores, an address arbitrator, where one or more processing cores are configured to submit a lock transaction request to the address arbitrator corresponding to a specific instruction in response to the execution of the specific instruction. The lock transaction request includes a lock variable address asserted on an address bus. The processor further includes a lock controller for performing lock transaction processing in response to the lock transaction request, and notifying processing result to the processing core from which the lock transaction request was sent. The processor further includes a switching device, coupled to the address arbitrator and the lock controller, for identifying the lock transaction request and notifying the lock transaction request to the lock controller.