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