The powertop application measures per-module power consumption and supports interactively optimizing power consumption:

With no options, powertop presents a display on the terminal:

# powertop

The powertop command takes measurements and displays detailed information about power usage, the processes using the most power, and so on:

PowerTOP 2.3  Overview  Idle stats  Frequency stats  Device stats  Tunable

Summary: 1146.1 wakeups/sec,  0.0 GPU ops/secs, 0.0 VFS ops/sec and 73.0% C

Usage Events/s Category Description
407.4 ms/s 258.7 Process /usr/lib/vmware/bin/vmware
64.8 ms/s 313.8 Process /usr/lib64/firefox/firefox

The -html tag will cause powertop to take measurements over a period of time and generate an HTML report with the default filename PowerTOP.html, which you can open using any web browser:

    # powertop --html

In the interactive mode, you can optimize power usage. When powertop is running, use the arrow or tab keys to switch to the Tunables tab; this shows a list of attributes powertop can tune to for consuming less power. Choose the ones you want, press Enter to toggle from Bad to Good.