One embodiment of the present invention provides a system that facilitates
changing a clock frequency in a memory system. During operation, the
system receives a command to change the clock frequency to a new clock
frequency. The system then iteratively changes the clock frequency to the
new clock frequency. More specifically, the system starts an iteration by
slewing the clock frequency toward the new clock frequency by an
increment to reach an intermediate frequency without interfering with
normal memory-system operation. Next, the system signals a memory
controller to pause normal memory system operation by completing or
cancelling all in-flight or outstanding memory system operations and not
accepting additional memory operation requests. Upon receiving an
acknowledgement from the memory controller that all in-flight or
outstanding memory operations have completed or terminated, the system
signals the memory controller to cause a delay-locked loop (DLL) inside
the memory system to relock to the intermediate frequency. When the DLL
relocks to the intermediate frequency, the system completes the iteration
by resuming normal memory system operation.