long flight; need battery power!

[Dan Langille]

On 26 Aug 2005 at 8:55, Kevin Oberman wrote:

> > From: "Dan Langille" <dan at langille.org>
> > Date: Thu, 25 Aug 2005 22:42:47 -0400
> > Sender: owner-freebsd-mobile at freebsd.org
> > 
> > In September, I'll have a couple of long flights.  I'll be using my 
> > IBM ThinkPad T41 to catch up on some long delayed FreshPorts 
> > enhancements.  Apart from charging whenever I can, I'm afraid I'll 
> > get only about 140-150 minutes from my battery.
> > 
> > Apart from buying a second battery, any ideas?
> 
> This gets a bit long, but I've been spending a lot of my spare time
> testing this stuff and it's proven interesting.
> 
> What version of FreeBSD are you running? V6 has a lot better power
> management than V5 and current is better, still. If you are running
> V6, get the powerd from HEAD and use that or just keep the CPU fairly
> slow.

This is what I'm using:
FreeBSD laptop.unixathome.org 6.0-CURRENT FreeBSD 6.0-CURRENT #10: 
Fri Jul 15 23:37:23 EDT 2005     
dan at lux.exampel.org:/usr/obj/usr/src/sys/LAPTOP  i386

> 'sysctl dev.cpu.0' will show (among other things) the available
> performance settings. Please remember that these are
> 'pseudo-frequencies' obtained by combining actual CPU clock settings
> with throttling and not just actual clock speed changes.

Wow.. .lots in there:

$ sysctl dev.cpu.0
dev.cpu.0.%desc: ACPI CPU
dev.cpu.0.%driver: cpu
dev.cpu.0.%location: handle=\_PR_.CPU_
dev.cpu.0.%pnpinfo: _HID=none _UID=0
dev.cpu.0.%parent: acpi0
dev.cpu.0.freq: 350
dev.cpu.0.freq_levels: 1400/22000 1225/19250 1200/18000 1050/16500 
1000/14000 900/13500 875/13750 800/10000 750/11250 700/11000 625/8750 
600/6000 525/8250 500/7000 450/6750 400/5000 375/5250 350/5500 
300/4500 250/3500 225/2250 200/2500 175/2750 150/2250 125/1750 
100/1250 75/750

> You can use several tools to see the actual CPU speed. I use the
> gkx86info2 plugin for gkrellm2.

> If you are just editing, a very low speed is the winner. Turn off
> powerd (if you are running it) and just set he CPU to the lowest
> performance available. If you are compiling, bump it up to the lowest
> native CPU speed. For debug, it depends, but I suspect you want lowest,
> again.

I plan to be doing a combination of coding and running database 
queries.  But I'll try to do some testing before I go...
-- 
Dan Langille : http://www.langille.org/
BSDCan - The Technical BSD Conference - http://www.bsdcan.org/