cancel
Showing results for 
Search instead for 
Did you mean: 

Server Gurus Discussions

kkanungo17
Journeyman III

What exact parts of the CPU are recorded by the RAPL registers?

Hi,

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?

Regards,

Koustuv

0 Likes
3 Replies
dipak
Staff
Staff

Re: What exact parts of the CPU are recorded by the RAPL registers?

Thank you for your query. Our AMD Server Gurus community seems to be better place to ask this query, so I'm moving this post there.

Thanks.

0 Likes
hardcoregames_
Big Boss

Re: What exact parts of the CPU are recorded by the RAPL 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

http://web.eece.maine.edu/~vweaver/projects/rapl/rapl-read.c 

0 Likes
vmjfk
Staff
Staff

Re: What exact parts of the CPU are recorded by the RAPL registers?

More information can be found in the EPYC PPR PG 161, found here, though context is scant. 

https://developer.amd.com/wp-content/resources/55803_0.54-PUB.pdf 

0 Likes