power-profiles-daemon

Most distributions install power-profiles-daemon by default with their GNOME and KDE desktop environments. This article compares TLP and power-profiles-daemon and explains how to replace the latter with TLP.

Does power-profiles-daemon achieve better power savings than TLP?

power-profiles-daemon covers only a subset of TLP’s settings:

PLATFORM_PROFILE_ON_AC/BAT
CPU_ENERGY_PERF_POLICY_ON_AC/BAT
CPU_BOOST_ON_AC/BAT

Due to the choice of settings, power-profiles-daemon represents a CPU throttle which mainly takes effect when the CPU is under load by applications. power-profiles-daemon does not include any settings to reduce power consumption when the CPU is idle like TLP provides them.

So it depends on your workload:

If the laptop often runs under medium or high load (e.g. video playback, compiling, etc.), then power-profiles-daemon using its power-saver profile may achieve savings similar to TLP
When the laptop is mostly idle or running with low load (e.g. text editing, browsing, etc.), then TLP offers advantages over power-profiles-daemon

Finally, note that the TLP’s default settings do not enable PLATFORM_PROFILE_ON_AC/BAT and CPU_BOOST_ON_AC/BAT. To achieve truly comparable results, they must be explicitly configured in TLP. One also needs to know that many (especially older) laptops do not support PLATFORM_PROFILE_ON_AC/BAT.

Conclusion: to find out which tool ultimately delivers better results, do comparative measurements on your target hardware with your usage pattern.

Does power-profiles-daemon conflict with TLP?

Yes. power-profiles-daemon uses kernel settings that TLP also controls (see above). Using both tools simultaneously means that TLP’s settings get overwritten by power-profiles-daemon (and vice versa) resulting in unpredictable outcomes for the settings in question.

For this reason many distributions prevent the simultaneous installation of their packages for TLP and power-profiles-daemon. In all other cases, uninstalling power-profiles-daemon is recommended.

How can I achieve the effect of power-profiles-daemon with TLP?

First of all, it is important to understand the fundamental differences between the two tools:

TLP implements an “automatic transmission”. Depending on the power source the corresponding one of the two settings profiles AC or BAT is applied automatically.
power-profiles-daemon implements a “manual transmission”, meaning there are three profiles (“gears”) power-saver, balanced and performance, which you have to select manually via the panel applet. Nothing happens automatically. The preset profile is balanced.
power-profiles-daemon’s profiles’ settings are hardcoded, while TLP’s profiles can be customized as desired.

From what has been said above, it is clear that the behavior of power-profiles-daemon cannot be completely reproduced with TLP. It is possible to map two of power-profiles-daemon’s profiles to the AC and the BAT profile of TLP as shown in the following examples:

Example 1: map balanced to AC and power-saver to BAT

PLATFORM_PROFILE_ON_AC=balanced
PLATFORM_PROFILE_ON_BAT=low-power

CPU_ENERGY_PERF_POLICY_ON_AC=balance_performance
CPU_ENERGY_PERF_POLICY_ON_BAT=power

CPU_BOOST_ON_AC=1
CPU_BOOST_ON_BAT=0

Example 2: map performance to AC and balanced to BAT

PLATFORM_PROFILE_ON_AC=performance
PLATFORM_PROFILE_ON_BAT=balanced

CPU_ENERGY_PERF_POLICY_ON_AC=performance
CPU_ENERGY_PERF_POLICY_ON_BAT=balance_performance

CPU_BOOST_ON_AC=1
CPU_BOOST_ON_BAT=0

Last but not least you may select TLP’s profile manually with a terminal command:

sudo tlp ac
sudo tlp bat