Power monitoring permissions

In recent kernel versions, precise power monitoring is only accessible to root users to prevent using it as a side-channel attack. In order to get the power monitoring output you'll need to give the palantir user access to this data using the following steps.

• Create a group using

  sudo groupadd powermonitoring
  

• Create /etc/udev/rules.d/99-powermonitoring.rules with

  SUBSYSTEM=="powercap", ACTION=="add", RUN+="/bin/chgrp -R powermonitoring /sys%p", RUN+="/bin/chmod -R g=u /sys%p"
  SUBSYSTEM=="powercap", ACTION=="change", ENV{TRIGGER}!="none", RUN+="/bin/chgrp -R powermonitoring /sys%p", RUN+="/bin/chmod -R g=u /sys%p"
  

• Apply the udev rules

  sudo udevadm control --reload-rules && sudo udevadm trigger
  

• Add your user to the group

  sudo usermod -a -G powermonitoring palantir
  

• Verify that you can read energy usage

  sudo su - palantir -c 'cat /sys/class/powercap/intel-rapl:0:0/energy_uj'