Powertop

Summary
This article discusses solving common power saving tasks, with use of Intel "PowerTOP" utility.
Important pages
Official site
Project page
Wikipedia article
Related
Laptop Mode Tools

PowerTOP is a tool provided by Intel to enable various powersaving modes in userspace, kernel and hardware. It is possible to monitor processes and show which of them are utilizing the CPU and wake it from its Idle-States.

Installation

Install package powertop, available in Official Repositories.

Powertop was updated to 2.0 which comes with more features (Article from the H Open). For more information, see the Release Announcement.

Tips and tricks

PowerTOP suggests a few methods to reduce the power consumption further. However, in the console, PowerTOP does not display the parameters. To find out which ones are suggested, proceed as follows:

• If you have changed parameters (e.g. in PowerTOP), reboot so that the system has default state of the parameters.
• Use PowerTOP to produce a report on parameters: # powertop --html=powerreport.html
• The last tab of the report now shows the actual parameters suggested by the tool to apply to save power.

You can apply these settings at boot by using module parameters, udev rules and sysctl. For details, see the power saving page.

Troubleshooting

Error: Cannot load from file

If you get an error like the following when starting powertop, you are likely to have powertop not allowed collecting enough measurement data yet. All you need to do is to keep powertop running for a certain time whilst being on battery.

Loaded 39 prior measurements
Cannot load from file /var/cache/powertop/saved_parameters.powertop
Cannot load from file /var/cache/powertop/saved_parameters.powertop