A system and method for efficient reporting of power usage. A power reporting unit within a processor receives a power consumption number once every sample interval from a power monitor. The power monitor determines a power consumption number based on sampled signals within one or more functional blocks in the processor, rather than based on temperature. An average power consumption number is computed based on received power consumption numbers for a running time interval, wherein the running time interval is larger than the sample interval. This value is conveyed to an external agent. Responsive to receiving and processing the average power consumption number, the external agent may cause changes in a cooling system.