i7z should show clock modulation value

[haarp]

Some Intel systems can throttle the CPU by employing a mechanism called clock modulation. What this does is disable the clock for a given percentage of a timeslice, slowing the core down. This is often used when the CPU is overheating or consuming too much power.

It is not easy to spot however. It is observable when C0% shrinks despite a core being fully loaded, but that is hard to track down.

Clock modulation can be observed in MSR 0x19A.
bit[4] is a binary value that shows whether clockmod is enabled.
bit[3:1] is a number that describes how many 12.5% steps of original CPU power remains.
(I count from 0)

e.g. 0b10100 -> clockmod enabled, 2 steps (25%) power remain -> The core will be switched off for 75% of its operation, and C0% will likely read close to 25 if the core is fully loaded.

Clockmod is present on Core2 and Nehalems, I don't know if it still applies to newer Core-i.

As it's hard to tell if clock modulation is in use, showing it in i7z would be very useful. Thanks!