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3.2.3. Tuning CPUfreq Policy and Speed
Once you've chosen an appropriate CPUfreq governor, you can further tune the speed of each CPU using the tunables found in /sys/devices/system/cpu/[cpu ID]/cpufreq/. These tunables are:
cpuinfo_min_freq — Shows the CPU's available minimum operating frequency (in KHz).
cpuinfo_max_freq — Shows the CPU's available maximum operating frequency (in KHz).
scaling_driver — Shows what CPUfreq driver is used to set the frequency on this CPU.
cpuinfo_cur_freq — Shows the current speed of the CPU (in KHz).
scaling_available_frequencies — Lists available frequencies for the CPU, in KHz.
scaling_min_freq and scaling_max_freq — Sets the policy limits of the CPU, in KHz.
Important
When setting policy limits, you should set scaling_max_freq before scaling_min_freq.
affected_cpus — Lists CPUs that require frequency coordination software.
scaling_setspeed — Used to change the clock speed of the CPU, in KHz. You can only set a speed within the policy limits of the CPU (as per scaling_min_freq and scaling_max_freq).
To view the current value of each tunable, use cat [tunable]. For example, to view the current speed of cpu0 (in KHz), use:
To change the value of each tunable, use echo [value] > /sys/devices/system/cpu/[cpu ID]/cpufreq/[tunable]. For example, to set the minimum clock speed of cpu0 to 360 KHz, use:
