I'm using an EPYC-7551 CPU on Ubuntu 18.04, Linux 4.15, and I see that there are 2 RAPL registers, CORE_ENERGY and PKG_ENERGY. Is there any documentation on which exact parts are recorded by these registers?
RAPL registers are now appearing widely in processors including server and consumer models. They exist on processors from Sandy Bridge onwards. AMD Ryzen also support them and so does AMD Epic.
In brief, if you have looked at the task manager for Windows 10 version 1903 or server version 1903 you will notice an energy column in the task list.
here is some code in C to read them but its fairly complex