Feature: CPU power usage from intel-rapl #602

Has this issue been covered in the Wiki?

• I have read the Wiki and my issue is not covered.

Is there an existing issue reported already?

• I have searched the existing issues, it does not exist. (This is similar to power usage is set to 0.0w while plugged in, fully charged #223 but proposes a solution)

Describe the new feature you would like

While charging, the battery's power rate is positive (or +0.0W when fully charged).

I'd like to be able to see the power usage of the CPU, since +0.0W doesn't tell me much. This is possible at least with Intel CPUs.

It looks like Mission Center is able to do this by measuring the rate of change of /sys/class/powercap/intel-rapl:0/energy_uj:

• Feature request with example script: https://gitlab.com/mission-center-devs/mission-center/-/work_items/200
• Implementation PR: https://gitlab.com/mission-center-devs/gng/-/merge_requests/34/diffs
• Another (more succinct) implementation: https://gitlab.com/jlo62/dotties/-/blob/master/.config/eww/code/get_sysinfo/src/cpu.rs?ref_type=heads#L79

Screenshots

The battery power rate is +0.0W:

Mission Center shows my CPU's power usage is -24.2W:

Anything else?

I think we should expose all the powercap entries including the other intel-rapl ones. On my laptop I have several energy values, though I don't know the difference between them.

❯ for f in /sys/class/powercap/*/energy_uj; do echo "$f:  $(cat $f)"; done
/sys/class/powercap/intel-rapl:0:0/energy_uj:        11069487836
/sys/class/powercap/intel-rapl:0:1/energy_uj:          648112110
/sys/class/powercap/intel-rapl:0:2/energy_uj:         2452401924
/sys/class/powercap/intel-rapl:0/energy_uj:          20214114572
/sys/class/powercap/intel-rapl:1/energy_uj:          27418821592
/sys/class/powercap/intel-rapl-mmio:0:0/energy_uj:    2452402840
/sys/class/powercap/intel-rapl-mmio:0/energy_uj:     20214134408