Characterizing Processors for Energy and Performance Management

A processor executes a computing job in a certain number of clock cycles. The clock frequency determines the time that the job will take. Another parameter, cycle efficiency or cycles per joule, determines how much energy the job will consume. The execution time measures performance and, in combination with energy dissipation, influences power, thermal behavior, power supply noise and battery life. We describe a method for power management of a processor. An Intel processor in 32nm bulk CMOS technology is used as an illustrative example. First, we characterize the technology by H-spice simulation of a ripple carry adder for critical path delay, dynamic energy and static power at a wide range of supply voltages. The adder data is then scaled based on the clock frequency, supply voltage, thermal design power (TDP) and other specifications of the processor. To optimize the time and energy performance, voltage and clock frequency are determined showing 28% reduction both in execution time and energy dissipation.