DYNAMIC POWER MANAGEMENT IN REAL-TIME SYSTEMS

摘要

A Dynamic Sleep Controller (220) reduces power consumption by a processor (CPU 202) in a computer system by determining a maximum number of times (token count) that the processor (CPU 202) can incur a start-up delay after being placed into a low- power mode during a token period of time when executing a task for a token period of time. The processor (CPU 202) may be placed into the low-power mode by a sleep request signal (222) sent to a power and clock controller (230) while the processor (CPU 202) is executing the task in response to an idle indicator only if a current value of the token count assigned to the task is greater than zero. The current value of the token count is decremented each time the processor incurs a start-up delay in response to being awakened from the low-power mode. The current token count is reset to match the assigned token count at the end of each token period. Furthermore, wakeup may be anticipated to allow the processor (CPU 202) to be awakened preemptively by a preemptive wakeup signal (224) sent to an interrupt controller (210) which sends a wakeup request (214) to a power and clock controller (230).