Linuxconf Europe: Kernel Programming and Energy Efficiency

LinuxConf Europe is a very technical conference. One of the nicest features of this gathering
has been an overt recognition on behalf of the organisers, the UKUUG and GUUG, that
Linux is only a small component of a large software ecosystem; largely the GNU operating
system. Even more impressively, on Tuesday, the conference held an entire session
dedicated to hardware-related issues, specifically power management. At first this may not
appear to be the most interesting topic, but as the kernel continues to mature the
importance of power management is ever-increasing.
Arjan van de Ven of Intel began the session with an overview of common programming
techniques which are the largest wastes of power consumption: unnecessary polling of system
resources, insufficient caching of data being read from hard disk for example. These
examples were largely presented in the context of desktop applications, but the importance
and ramifications spread much further, most notably into the field of mobile devices.
Mobile and embedded Linux have been some of the largest growth areas for the kernel in
recent years (as advanced by devices such as Nokia's Internet Tablets, N770/800 and this
will only accelerate as OpenMoko and Qtopia phones become commercially viable.
The session ended with a talk by Matthew Garrett discussing how programmers need to go
about making Linux less power hungry. He noted that he had calculated his power saving
code, internationally, had saved more energy than he had consumed flying to conferences to
present his work. The ecological argument for this work is clearly apparent. However, it
shall be the increased usage time for mobile devices that will be the most obvious benefit of
this work.