Dynamic voltage and frequency scaling (DVFS) is performed based on a power step by setting a plurality of power levels corresponding to a plurality of available frequencies of a clock signal for an operation of a processor, setting a plurality of power steps corresponding to the plurality of available frequencies, and controlling a conversion between the plurality of power levels based on a utilization of the processor and the plurality of power steps. Performance and power consumption of a processor are controlled efficiently by performing power level conversion based on the power step.