1. A design structure embodied in a machine readable medium, the design structure comprising: a data processing circuit having an input and an output, said data processing circuit configured to generate an output data signal on said output based on an input data signal presented to said input; a power measurement circuit configured to measure an amount of electrical power consumed by said processing circuit in generating said output signal from said input signal, said power measurement circuit connected between said processing circuit and a power supply for said processing circuit; and a memory element configured to store a tag containing a value representing said amount of electrical power consumed by said processing circuit in generating said output data signal from said input data signal and either (a) said input data of said input data signal or (b) a pointer to said input data of said input data signal.