Fast smp/asmp mode-switching hardware apparatus for a low-cost low-power high performance multiple processor system

Abstract

A processing system includes multiple processors in which a first processor operates at a first clock frequency and first supply voltage at all times. At least one processor is dynamically switchable to operate at the first clock frequency and first supply voltage resulting in the first and second processors providing symmetrical multi-processing (SMP) or at a second clock frequency and a second supply voltage resulting in the first and second processors providing asymmetrical multi-processing (ASMP). An integrated controller (e.g., finite state-machine (FSM)) controls not only voltage change, but also clock-switching. Various criteria can be used to determine when to switch the at least one switchable processor to improve power consumption and/or performance. Upon receipt of a switching command to switch between SMP and ASMP, a series or sequence of actions are performed to control a voltage supply and CPU/memory clock to the switchable processor and cache memory.