Power consumption of developed OpenCL application

I'm trying to measure the power consumption of an hybrid CPU+GPU OpenCL application I have developed. As of Ivy Bridge, AFAIK, ther power consumption registers or flags which can be read and profiled in order to obtain an estimate on the power consumption of the processor (both CPU and GPU) during the kernel run. As I recall from the poor and scattered information I could gather, this can be done similarly to the procedure used when reading the TSC counter.

What I was trying to know is:

First, where to start? What is the proper source of documentation, the whole IS?

Second, should an external application be used for simplicity? What app should be used then?

Thank you.