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:

  • powersave – kernel default
  • performance
  • schedutil - kernel default for certain hardware that uses intel_pstate passive mode

acpi-cpufreq

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

  • ondemand – kernel default (for most distributions)
  • schedutil
  • powersave
  • performance
  • conservative

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

Important

powersave for intel_pstate and ondemand for acpi-cpufreq are power efficient for almost all workloads and therefore kernel and most distributions have chosen them as defaults; 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:

  • Requires Intel Core i CPU and the intel_pstate scaling driver
  • HWP.EPP requires kernel 4.10 and Intel Core i Gen. 5 (Skylake) or newer CPU
  • EPB requires kernel 5.2 or module msr and x86_energy_perf_policy from linux-tools
  • 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 Intel Core i Gen. 5 (Skylake) or newer CPU and the intel_pstate scaling driver
  • Requires kernel 4.10
  • 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 Core i processors. Values are stated as a percentage (0..100%) of the total available processor performance.

Hints:

  • Requires the intel_pstate scaling driver
  • 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

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

Hints:

  • A value of 1 does not activate boosting, it just allows it
  • This may conflict with your distribution’s governor settings

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 the intel_pstate scaling driver
  • 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