How to limit Power Consumption under high CPU Load?¶
The intel_pstate scaling driver offers this possibility. Use the settings
with nn < 100 to achieve it. Refer to CPU_MIN/MAX_PERF_ON_AC/BAT.
- Check the output of tlp-stat -p to determine the active scaling driver
- This will not limit the power consumption of the GPU (neither for integrated nor for discrete graphics)
Frequency Scaling Settings do not get applied¶
Symptom: tlp-stat -p shows values that do not reflect configuration.
There are several possible causes:
Invalid frequency settings
Solution: tlp-stat -p tells the possible frequencies for your CPU. Example:
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies = 2400000 1600000 800000 [kHz]
No ondemand governor with intel_pstate
Symptom: tlp-stat -p displays
/sys/devices/system/cpu/cpu0/cpufreq/scaling_driver = intel_pstate /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor = powersave
Works as designed: since kernel 3.9 the new scaling driver intel_pstate is available and enabled by default on Intel Sandy Bridge (or newer) hardware. intel_pstate supports the governors powersave (recommended default) and performance only, ondemand is gone.
tlp-stat -p shows ‘x86_energy_perf_policy: program for your kernel not installed.’¶
Depending on the distribution your mileage may vary:
- Ubuntu: install the metapackage linux-tools-generic or linux-tools-generic-lts-* for HWE stack kernels, no package is available for mainline kernels.
- Debian: install the package linux-cpupower.
- Arch: install the package x86_energy_perf_policy.
- Fedora: install the package kernel-tools.