What's the correct measuring unit for power measurements

[lampajr]

Hello team,

I recently started playing a little bit with Kepler, and I am not expert on energy consumption measurements, so, sorry if I am saying something wrong.

Looking at the doc at https://github.com/sustainable-computing-io/kepler/blob/2d80bbda0e3ccad37f6fc45326f57fc67c4ee73f/docs/developer/power-attribution-guide.md I can see it is explicitly stated that the power measurements is computed in μW:

...
    Energy: Measured in microjoules (μJ) as cumulative counters from hardware
    Power: Calculated as rate in microwatts (μW) using Power = ΔEnergy / Δtime
...

Therefore I was expecting to get the same measurements in the exported Prometheus metrics, but it seems not the case.

I tried fetching kepler_node_cpu_watts metric that, as per my understanding is Node CPU Time = Σ(All process CPU time deltas), so it should be very similar (or at least of the same order of magnitude of direct RAPL measurements. And I noticed the values are very similar each other, therefore they should use the same measurements unit.. which is Watts for RAPL.

Now the questions, is the power measurements computed by Kepler in μW or W? or maybe the way those metrics are exported is different wrt to the internal measurement units. Can you please clarify this topic?

Thanks a lot!!!