SINGLE-CORE WAKEUP MULTI-CORE SYNCHRONIZATION MECHANISM

摘要

A microprocessor includes a plurality of cores, a shared cache memory, and a control unit that individually puts each core to sleep by stopping its clock signal. Each core executes a sleep instruction and responsively makes a respective request of the control unit to put the core to sleep, which the control unit responsively does, and detects when all the cores have made the respective request and responsively wakes up only the last requesting cores. The last core writes back and invalidates the shared cache memory and indicates it has been invalidated and makes a request to the control unit to put the last core back to sleep. The control unit puts the last core back to sleep and continuously keeps the other cores asleep while the last core writes back and invalidates the shared cache memory, indicates the shared cache memory was invalidated, and is put back to sleep.

主权项

1. A method for enabling most cores of a multi-core microprocessor to sleep while a designated one of the cores services non-directed wakeup events that are not directed to any specific core, the method comprising:
putting all of the cores to sleep and blocking wakeup events for all but a designated one of the cores, wherein said putting all of the cores to sleep comprises refraining from providing a clock signal and a power source to all of the cores; in response to detecting a wakeup event, waking up the designated core to handle the detected wakeup event; unblocking the wakeup events for the cores other than the designated core, regardless of whether there is any non-designated core to which a pending wakeup event is directed, so that in an event that a directed wakeup event is directed to a non-designated core, the non-designated core is enabled to respond to the directed wakeup event, and in an event that no directed wakeup event is directed to a non-designated event, all of the non-designated cores remain asleep; putting the designated core back to sleep after the designated core services the wakeup event; blocking wakeup events for all but the designated core; keeping the other cores asleep, after said putting all of the cores to sleep, until a wakeup event is directed to one or more of the other cores.