cpufreq-info:tldr:f46b2

The command cpufreq-info -l is used to display the available CPU frequency scaling (cpufreq) states or performance levels on a Linux system.

When a processor operates at a higher frequency, it consumes more power and generates more heat. CPU frequency scaling allows the operating system to dynamically adjust the CPU frequency based on the current system load or power management settings. This can help optimize power consumption and reduce heat generation.

The -l option is used to list the available frequency states or performance levels that the CPU can operate in. These states generally include the minimum and maximum frequencies supported by the CPU, as well as intermediate frequencies at which the CPU can run.

By executing cpufreq-info -l, you will get a list of available frequency states along with their corresponding frequencies. For example, the output may look like this:

analyzing CPU 0:
  available frequency steps: 2.40 GHz, 2.20 GHz, 2.00 GHz, 1.80 GHz
  hardware limits: 1.20 GHz - 2.40 GHz
  available cpufreq governors: performance, powersave

This output indicates that the processor can operate at frequencies of 2.40 GHz, 2.20 GHz, 2.00 GHz, and 1.80 GHz. The hardware limits specify the minimum and maximum frequencies supported by the CPU (1.20 GHz to 2.40 GHz in this case), and the available cpufreq governors determine the CPU frequency scaling policy (performance or powersave in this case).

By knowing the available frequency states, one can manually set the CPU frequency to a specific level using tools like cpufreq-set or select the appropriate cpufreq governor for automated frequency scaling.