"What's eating the battery life of my laptop?" Arjan van de Ven rhetorically asked in an announcement about a new PowerTOP utility released by Intel for detecting what Linux programs and kernel tunables are resulting in the most power consumption. "Why isn't it many more hours? Which software component causes the most power to be burned? These are important questions without a good answer... until now." Arjan went on to describe the new tickless kernel feature that was merged in 2.6.21-rc1 [story] noting that it can help reduce power consumption by allowing the CPU to remain idle for longer periods, "current processors save a lot of power if they are idle for long periods, which translates into a longer battery life for your laptop, or a lower energy bill for your datacenter." He continued on to describe the new utility:

"Intel is proud to announce the PowerTOP tool, a program that collects the various pieces of information from your system and presents an overview of how well your laptop is doing in terms of power savings. In addition, PowerTOP will provide an indication of which tunables and software components are the biggest offenders in slurping up your battery time. PowerTOP will update it's display frequently so that you can directly see the impact of any changes you are making."

From: Arjan van de Ven [email blocked]
To: Linux Kernel Mailing List [email blocked]
Subject: [announce] Intel announces the PowerTOP utility for Linux
Date:	Fri, 11 May 2007 16:07:18 -0700


What's eating the battery life of my laptop? Why isn't it many more 
hours? Which software component causes the most power to be burned? 
These are important questions without a good answer... until now.

The Linux 2.6.21 kernel introduces the so called tickless-idle 
feature. This feature allows the processor to be really idle for long 
periods of time, rather than having to wake up every millisecond for 
the timer tick. Current processors save a lot of power if they are 
idle for long periods, which translates into a longer battery life for 
your laptop, or a lower energy bill for your datacenter. However, a 
Linux system consists of more software than just the kernel, and there 
are many tunables involved. It's not easy to see what is going on, and 
as a result the behavior is sometimes far from optimal, and a lot of 
power is wasted.

Intel is proud to announce the PowerTOP tool 
(http://www.linuxpowertop.org), a program that collects the various 
pieces of information from your system and presents an overview of how 
well your laptop is doing in terms of power savings. In addition, 
PowerTOP will provide an indication of which tunables and software 
components are the biggest offenders in slurping up your battery time. 
PowerTOP will update it's display frequently so that you can directly 
see the impact of any changes you are making.

A typical Linux distribution has many components that wake the 
processor up frequently for no good reason. In our testing with 
PowerTOP, we have seen many cases where with some simple fixes, the 
battery life of typical laptops was increased by one hour or more!

We are providing fixes for several of the issues we identified, and we 
encourage the Linux community to help us in this quest to get the 
maximum battery life out of your (hopefully Intel based) laptops. Try 
the PowerTOP tool, join the mailing list or the IRC channel and 
provide feedback, problem reports or fixes!

Website:      http://www.linuxpowertop.org
IRC:          irc.oftc.net    #powertop channel
Mailing list: http://www.bughost.org/mailman/listinfo/power

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