MSR_CORE_PERF_LIMIT_REASONS

[berga_d]

Hi Martin, it seems Intel recently updated MSRs docs (page 35-142) about Haswell (and Broadwell): they've added three very interesting MSRs that show the exact reason(s) why CPU, GPU or Uncore are slowed down in real-time. (like PROCHOT, Thermal, Graphics driver, Low Utilization, VRM Therm Alert, Electr. Current,.... ). I've read them "manually" and they work.
Can you add reporting these info in a next beta? It's useful to know the true cause of frequency clipping. I think you should add three "text sensors", as these can't be synthesized in a numeric way. Thanks!

 

[Martin]

I have been thinking about reporting this for some while Though I have seen different descriptions of reasons in those registers in other documents, so I'm not sure what is correct.
The current interface would need to be adjusted to be able to report such values...

 

[berga_d]

Thanks!
Can you write me which other documents refer to these msrs? So I can cross-check them, at least in regard to Temp, Current and TDP limits.

 

[Martin]

I'm sorry, but those are not public documents.

 

[berga_d]

I supposed they were under NDA, I've found anything the net.
I've written a small reporting program and made some testing: it seems the MSRs descriptions in the public documents are correct.
Bye!