Reducing save restore latency for power control based on write signals

Abstract

A method of save-restore operations includes monitoring, by a power controller of a parallel processor (such as a graphics processing unit), of a register bus for one or more register write signals. The power controller determines that a register write signal is addressed to a state register that is designated to be saved prior to changing a power state of the parallel processor from a first state to a second state having a lower level of energy usage. The power controller instructs a copy of data corresponding to the state register to be written to a local memory module of the parallel processor. Subsequently, the parallel processor receives a power state change signal and writes state register data saved at the local memory module to an off-chip memory prior to changing the power state of the parallel processor.