Fix RAPL DRAM energy unit for Sapphire Rapids (SPR)

[chriswasser]

Hi @TomTheBear,

this PR directly addresses the issue reported in #642. Although the implemented changes are really minor, I tested it on our system and the reported numbers are indeed ~4 times higher (new 61 uJ / old 15,3 uJ = 3,9869281).

Greetings

Christian

[ipatix]

Good catch. Thanks for the discovery. The energy unit has indeed changed for Sapphire Rapids.

[chriswasser]

Hi Michael,

Thanks for the quick feedback. And sorry to have addressed Thomas directly - I did not know he had a new helping hand in maintaining LIKWID 😃 Glad to see the continued development 👌

Greetings from Aachen,

Christian

[hservatg]

Certainly.

According to Table 2-52 (Additional MSRs Supported by the 4th and 5th Generation Intel Xeon Scalable Processor Families) from the Intel SDM (as of October 2024 - Volume 4) one can read for Register Address: 619h, 1561 -- bits 31:0

Energy in 61 micro-joules. Requires BIOS configuration to enable DRAM RAPL mode 0 (Direct VR)