Measure CPU power consumption of RPi3 with software

Question

I would like to measure the power consumption of RPi3's CPU. Is there a tool like NVidia's NVML that can give an estimation of the real-time power consumption of the Raspberry Pi 3?

I am aware of the fact that there is no tool for measuring the energy of the whole device but there might be a way of using external software tools, and maybe ARM provides something that can estimate the power usage.

I need to read the power consumption in an automated way and save it into the device. I use software to automatically tune the parameters of an application and the power consumption should be provided real time within the software.

Answer 1

I don't know of any native power measurement functionality built into either the Pi or the Arm chip, but there are a couple of options that will get you close to what you desire.

You could use a inline USB Volt/Amp meter like this one, or a Kill A Watt.

Together with a little Math these should give you what you need.

Answer 2

To got a bit further then Steve Robillard, I would use the result of top command, showing CPU usage in %, as a base of calculus. As top gives CPU usage over different periods, it will suit any of your need.

Now that we can see our CPU usage, it's trivial to measure RPI consumption under different load (using any multimeter), and find either a formula that links these values, either a table that will associate CPU % usage slices and mA consumption.

Note : if CPU % usage isn't enough reliable, cpu temperature could also give a hint on power consumption. You can get this value with : /opt/vc/bin/vcgencmd measure_temp