Intel® Power Gadget is a software-based power estimation tool enabled for 2nd Generation Intel® Core™ processors or newer. It provides real-time processor package power information in watts using energy counters.
Dongjin Son, B. Krishnamachari, and J. Heidemann. Sensor and Ad Hoc Communications and Networks, 2004. IEEE SECON 2004. 2004 First Annual IEEE Communications Society Conference on, page 289-298. (October 2004)