Processor

CPU_SCALING_GOVERNOR_ON_AC/BAT

CPU_SCALING_GOVERNOR_ON_AC=powersave
CPU_SCALING_GOVERNOR_ON_BAT=powersave

Selects the CPU scaling governor for automatic frequency scaling. Configuration depends on the active scaling driver:

intel_pstate

For Intel Core i 2nd gen. (“Sandy Bridge”) or newer Intel CPUs. Supported governors are:

  • performance

  • powersave – default

intel_cpufreq

Starting with kernel 5.7, the intel_pstate scaling driver selects “passive mode” aka intel_cpufreq for CPUs that do not support hardware-managed P-states (HWP), i.e. Intel Core i 5th gen. or older.

Supported governors are identical to the acpi-cpufreq driver below, the default scheduler is schedutil.

acpi-cpufreq

For AMD, other brands and older Intel CPUs. Supported governors are:

  • conservative

  • ondemand – default for most distributions

  • userspace

  • powersave

  • performance

  • schedutil – default for newer kernels and the intel_cpufreq driver above

Note

Refer to the output of tlp-stat -p to determine the active scaling driver and available governors.

Important

Default governors listed above are power efficient for almost all workloads, therefore kernel devs and most distributions have chosen them as such. If you still want to change the scaling governor, you should know what you’re doing!

CPU_SCALING_MIN/MAX_FREQ_ON_AC/BAT

CPU_SCALING_MIN_FREQ_ON_AC=0
CPU_SCALING_MAX_FREQ_ON_AC=9999999
CPU_SCALING_MIN_FREQ_ON_BAT=0
CPU_SCALING_MAX_FREQ_ON_BAT=9999999

Set the min/max frequency available for the scaling governor. Possible values depend on your CPU. For available frequencies consult the output of tlp-stat -p.

Hints:

  • Do not use this setting with the intel_pstate scaling driver, use CPU_MIN/MAX_PERF_ON_AC/BAT instead

  • Min/max frequencies have to be specified for battery and AC modes

  • To enable processor defaults comment all four settings and reboot

  • Lowering the max frequency on battery power does not conserve power; best results are achieved by the ondemand governor without frequency limits

CPU_ENERGY_PERF_POLICY_ON_AC/BAT

Version 1.3 and higher

CPU_ENERGY_PERF_POLICY_ON_AC=balance_performance
CPU_ENERGY_PERF_POLICY_ON_BAT=balance_power

Set Intel CPU energy/performance policies HWP.EPP and EPB (in order of increasing power saving):

  • performance

  • balance_performance

  • default

  • balance_power

  • power

Default when unconfigured: balance_performance (AC), balance_power (BAT)

Hints:

  • HWP.EPP (hardware-managed P-states): requires kernel 4.10, intel_pstate scaling driver and Intel Core i 6th gen. (“Skylake”) or newer CPU

  • EPB: requires kernel 5.2 (or module msr and x86_energy_perf_policy from linux-tools), intel_pstate or intel_cpufreq scaling driver and Intel Core i 2nd gen. (“Sandy Bridge”) or newer CPU

  • When HWP.EPP is available, EPB is not set

CPU_HWP_ON_AC/BAT

Version 1.2.2 and lower

CPU_HWP_ON_AC=balance_performance
CPU_HWP_ON_BAT=balance_power

Set Intel CPU energy/performance policy HWP.EPP. Possible values are (in order of increasing power saving):

  • performance

  • balance_performance

  • default

  • balance_power

  • power

Hints:

  • Requires kernel 4.10, intel_pstate scaling driver and Intel Core i 6th gen. (“Skylake”) or newer CPU

  • For version 1.3 and higher this parameter is replaced by CPU_ENERGY_PERF_POLICY_ON_AC/BAT

CPU_MIN/MAX_PERF_ON_AC/BAT

CPU_MIN_PERF_ON_AC=0
CPU_MAX_PERF_ON_AC=100
CPU_MIN_PERF_ON_BAT=0
CPU_MAX_PERF_ON_BAT=30

Define the min/max P-state for Intel CPUs. Values are stated as a percentage (0..100%) of the total available processor performance.

Hints:

  • Requires intel_pstate or intel_cpufreq scaling driver and Intel Core i 2nd gen. (“Sandy Bridge”) or newer CPU

  • The driver imposes a limit > 0 on the min P-state, see min_perf_pct in the output of tlp-stat -p

  • This setting is intended to limit the power dissipation of the CPU

CPU_BOOST_ON_AC/BAT

CPU_BOOST_ON_AC=1
CPU_BOOST_ON_BAT=0

Configure CPU “turbo boost” (Intel) or “turbo core” (AMD) feature (0 = disable / 1 = allow).

Note

A value of 1 does not activate boosting, it just allows it.

SCHED_POWERSAVE_ON_AC/BAT

SCHED_POWERSAVE_ON_AC=0
SCHED_POWERSAVE_ON_BAT=1

Minimize number of used CPU cores/hyper-threads under light load conditions (1 = enabled, 0 = disabled). Depends on kernel and processor model.

Default when unconfigured: 0 (AC), 1 (BAT)

ENERGY_PERF_POLICY_ON_AC/BAT

Version 1.2.2 and lower

ENERGY_PERF_POLICY_ON_AC=performance
ENERGY_PERF_POLICY_ON_BAT=power

Set Intel CPU energy/performance policy EPB. Possible values are (in order of increasing power saving):

  • performance

  • balance-performance

  • default (deprecated: normal)

  • balance-power

  • power (deprecated: powersave)

Hints:

  • Requires intel_pstate or intel_cpufreq scaling driver and Intel Core i 2nd gen. (“Sandy Bridge”) or newer CPU

  • Requires the kernel module msr and the tool x86_energy_perf_policy matching your kernel version

  • For version 1.3 and higher this parameter is replaced by CPU_ENERGY_PERF_POLICY_ON_AC/BAT

See also