[SavantIdiot]

This is precisely why all of the large volume cloud server farms I worked with turn off throttling: they need 100% predictable CPU utilization. I worked on power control strategies at Intel for quite some time, and we would often joke in server (Xeon) parts that it was pointless because all of our work was disabled.

Early throttles were 50% duty cycles, then L1 bubble injections, then V/F frequency scaling. The author only addresses the early mechanisms, but it gets even more complex with the PCUs in the later Xeons.

It is not an easy question to answer, but I think the question can be modified. A single number doesn't solve the problem, you need to know utilization in the context of throttling (and magnitude). Then decide what you are trying to solve: scheduling or app-level throttling? Personally, the Hz denominator should change if it used in utilization , since that covers the majority of cases. Any other case should read both metrics.

EDIT: Removed generalization and worded as anecdote.

[jeffbee]

I have managed several extremely large fleets of computers and I can tell you they all use frequency scaling. I seriously doubt that your statement applies to "most server farms" when properly weighted.

[toast0]

It depends on who pays for power. When I was running a couple thousand machines on managed hosting, we disabled frequency scaling, because it wasn't our power bill and predictability and ease of measurement is nice. But at places where we paid for power, then frequency scaling was enabled (and sometimes they'd throttle things down to manage hot racks etc)

[SavantIdiot]

True, I should have more accurately said: all large volume cloud vendors I worked with.

[jeffbee]

So, you've never used GCE, EC2, or Azure? Because they all offer frequency scaling.

[SavantIdiot]

Yes, I use them all the time. Did you see the part where I was talking about my customers?