cpufreq-info
Display CPU frequency scaling information
TLDR
Show CPU frequency information for all CPUs
Show CPU frequency information for the specified CPU
Show the allowed minimum and maximum CPU frequency
Show the current minimum and maximum CPU frequency and policy in table format
Show available CPU frequency policies
Show current CPU work frequency in a human-readable format, according to the cpufreq kernel module
Show current CPU work frequency in a human-readable format, by reading it from hardware (only available to root)
SYNOPSIS
cpufreq-info [options]
PARAMETERS
--help
Display help text and exit.
--version
Display version information and exit.
-c CPU
Limit the output to information about a specific CPU core. CPU specifies the CPU number.
-d
Print debugging information.
DESCRIPTION
The cpufreq-info
command provides detailed information about the CPU frequency scaling capabilities of your Linux system. It reports on available CPU frequency governors, supported frequency ranges, and current operating frequencies for each CPU core. This tool is useful for understanding how your system manages CPU power consumption and performance. By examining the output, you can determine if frequency scaling is properly configured and identify potential issues related to performance throttling. The command relies on the cpufreq
subsystem within the Linux kernel to gather its data. It parses information from the /sys/devices/system/cpu/cpu*/cpufreq
directory. Note that the availability and specific details provided by cpufreq-info
depend on the kernel version, CPU architecture, and the presence of appropriate CPU frequency scaling drivers.
CAVEATS
The output and functionality of cpufreq-info
are heavily dependent on the Linux kernel's cpufreq
subsystem and the specific CPU frequency scaling drivers used. If these are not properly configured, the command may provide inaccurate or incomplete information.
INTERPRETING OUTPUT
The output typically includes information about:
Available CPU(s): The CPUs on which frequency scaling is enabled.
Driver: The kernel driver used for frequency scaling.
CPUs which run at the same hardware frequency: CPUs that share a frequency domain.
Hardware limits: The minimum and maximum supported frequencies.
Available governors: The available CPU frequency governors (e.g., performance, powersave, ondemand).
Current policy: The governor and frequency range currently in use.
Current Frequency: Current operating frequency of CPU
HISTORY
The cpufreq-info
command is part of the cpufrequtils
package, which has been available for many years in most Linux distributions. It was developed to provide a user-friendly interface to the cpufreq
subsystem of the Linux kernel, allowing users to easily query and monitor CPU frequency scaling settings. Historically, it has been a key tool for managing CPU power consumption on laptops and servers.