Arjan van de Ven wrote:
Hi,
some of you already know that I've been working on getting Linux (and
Fedora) to be a lot better about power usage on laptops by avoiding
spurious wakeups and context switches and such (look at the "wakeup" bug
in fedora bugzilla ;).
As part of my job at Intel I've now released a user friendly tool that
allows everyone that uses it to see what the biggest problems on their
own laptop are... The results internally to Intel have been really good;
several people gained an hour of battery just by using the tool and
getting rid of (or fixing) 'broken' applications.
PowerTOP can be downloaded from http://www.linuxpowertop.org
for completeness I've attached the full announcement text I used in
other places below. I hope that enough people will use it and report /
fix issues in software so that the whole Linux experience on laptops
will be a lot better in a few months..
----------------------
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
Cool thing, just tried it on rawhide with the not-so-unexpected result where the
top is liferea and epiphany followed by usb, XOrg and eth0.... But what I didn't
expect was the power usage and count of wakeups:
Wakeups-from-idle per second : 413.0
Power usage (ACPI estimate) : 1.1 W (2.4 hours left)
1.1 W? That is really low IMO... Really, really interesting. Hope this tool
helps to improve linux powersaving capabilities in the future. Keep the good
work :-)
Martin
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