CPU Instantaneous Power Consumption

From: pradeep hettiarachchi
Date: Mon Jun 20 2011 - 22:16:15 EST


I am a PhD student and doing a research which involves
control-theoretic real-time process/job scheduling. Here is my

I need to calculate the power consumption of a single or two CPU cores
and equivalent Thermal Dissipation accurately. I did not find any
supporting material from Intel to find the instantaneous power
consumption (and thermal dissipation) of the CPU. Therefore I am
trying some alternative path; I measure the CPU regulator input
current (using a very small shunt resister in series with 4 pin CPU
ATX connector). Also, assuming that the CPU voltage regulator operates
at 12 V rated, I could calculate the input power to the CPU regulator.

However without knowing the following I cannot complete my power calculation:

1) What is the DC-to-DC CPU regulator efficiency ?
2) What is the relationship between TDP and input power to the CPU ?
3) Do you suggest any other better method to calculate the
instantaneous input power to the CPU ?
(I can think of calculating accurate instantaneous CPU power as VID
(corresponding Vcc) x CPU_current_from_regulator; but, how do I read
instantaneous VID ? Is there any MSR that I can instantly access to
read VID ? (I think Intel has hidden theses details from system
developer) )

Please help me to find answers to these questions.


Pradeep M. Hettiarachchi
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/