Power Management

What is the role of a governor, such as a cpufreq governor, that sets CPU frequency in Linux and other OSes?

  1. ATo set the frequency at which CPUs are manufactured
  2. BTo change the color of the CPU cooling fan
  3. CTo choose frequency and voltage levels matching required performance, based on load such as CPU utilization
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Answer: C. To choose frequency and voltage levels matching required performance, based on load such as CPU utilization

A governor is a software policy that checks CPU load at intervals and selects operating levels, raising frequency when busy and lowering it when there is headroom. Policies include always maximum performance, always power saving and load-dependent scaling. On recent CPUs, hardware increasingly fine-tunes frequency itself, with the OS merely indicating whether to favor performance or efficiency.

  • A. It has nothing to do with manufacturing.
  • B. It has nothing to do with fan color.
  • C. Correct. Software balances performance and power.
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More Power Management questions

  1. Which describes CPU turbo operation (such as Turbo Boost)?
  2. Which describes thermal throttling?
  3. Some CPU power limits let the chip run above the long-term average limit (close to TDP) for short periods. Why does this work?
  4. What is the most suitable use of features such as Intel RAPL that let software measure CPU and memory power and set caps?
  5. Which describes ACPI, used in PCs and similar systems?