Linux Kernel 2.6.21 has been announced. Linus writes: "So the big change during 2.6.21 is all the timer changes to support a tickless system (and even with ticks, more varied time sources). Thanks (when it no longer broke for lots of people ;) go to Thomas Gleixner and Ingo Molnar and a cadre of testers and coders." More info here and here.
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Member since:2005-12-31
Perhaps this "benchmark" is worth something to you:
http://www.phoronix.com/scan.php?page=article&item=651&num=1
Member since:2005-07-08
Member since:2005-10-06
Seriously, Linux still doesn't match battery consumption of a 5+ years old Windows XP
Doesn't accord with my laptop experience - my "runtimes" were (freshly charged to total cutout):
XP - 2hrs 37mins
Xubuntu 6.06 - 3hrs 49mins
Odd one, that. Can't retest because that was before I completely killed my battery with overwork 
My main interest in a "tickless" kernel is for audio work - the kernel clock has fairly recently been changed from 1000hz to 250hz, and this blows out apps such as "Rosegarden", which has to be run on a specially compiled kernel. Even most of then low-latency audio kernels miss this trick - AFAIK only the 64studio distro has a low-latency 1000hz kernel. My hope is that if the clock is "off" when idle the kernel developers will turn it up to 1000hz again when it is going.
Member since:2006-09-01
Biteydog--- I do highly recommend rolling your own kernel for audio work. I was a complete newbie a few years ago and compiling my kernel was a daunting task, but it's actually pretty easy after the first couple tries. I guess what I mean to say is that changing the HZ setting from 250 back to 1000HZ is pretty easy (literally, the press of a few buttons) once you know how to roll your own.
Member since:2005-11-12
Member since:2005-07-13
Larry Finger maintains a cumulative patchset for released kernels with the latest wireless-dev stuff, it will cleanly apply to 2.6.21 if you want mac80211 and are going to roll your own anyways.
ftp://lwfinger.dynalias.org/patches/
There were some substantial improvements to the softmac bcm43xx drivers in 2.6.21. I can actually use my 4311 now without jumping through hoops; mac80211 is still a WIP, doesn't work well for all the chipsets yet. But still, it's nice to no longer curse my wifi or fiddle with ndiswrapper. With the latest development the bcm43xx team is doing, broadcom is becoming one of the better supported chipsets in the kernel... that speaks volumes to the work they've done...
Member since:
2006-01-17
I'm interested to find out how much battery 'performance' is improved with this kernel. Likely I'll install it in Feisty (and unfortunately loose new mac80211 bcm43xx driver that they pathched in, unless I do it myself).
Other important side is userspace. If HAL or any other daemon (or GNOME/KDE component, and even programs like web browser) polls something all the time, than of course CPU will not be idling that often (plus the additional overhead of frequent switching from/to powersave mode). Seriously, Linux still doesn't match battery consumption of a 5+ years old Windows XP, I hope this kernel will change it (along with optimization of userspace stuff).