15 Aug
2014
15 Aug
'14
10:22 p.m.
I verified that CPU freq requests were taken by reading out the PERF_STATUS register.
Don't use the x86 PERF_STATUS register -- it will not tell you what you want to know.
If you want to see the actual frequency, you need to watch how many cycles elapse per a known time interval, which is how intel_pstate and the turbostat utility do it.
cheers, Len Brown Intel Open Source Technology Center