Getting longer battery life with laptop-mode (was: Re: Installing Debian using debian-sarge-netinst.iso (powerpc))
On Mar 08 2004, Matijs van Zuijlen wrote:
> On Mon, Feb 23, 2004 at 04:07:07PM +0100, Pau Rul·lan Ferragut wrote:
> > Really? I thougth ext2 was better because it doesn't write
> > continuesly, so there is a battery saved.
>
> This used to be true: the standard commit interval for ext3 is 5
> seconds, which used to be hardcoded, but you can change that on recent
> kernels with the commit option. I have commit=3600, for 1 hour
> intervals.
I am currently seeing how to get longer battery life on my old i386 laptop
(and trying not to get crazy with my Desktop's noisy HD) and I'm trying to
experiment with making the disk spin up and down.
The advice for changing the commit time is nice.
> I also have:
>
> # cat /proc/sys/vm/bdflush
> 30 500 0 0 600000 600000 60 20 0
>
> This will stop the disk from spinning up every time things like gconfd,
> chrony, or galeon (or any other web browser with crash recovery) write
> stuff to disk (which is often).
I don't have this file. I am using a 2.6 kernel. I think that the above
applies only to Linux 2.4.
> And:
>
> # cat /proc/sys/vm/laptop_mode
> 1
>
> This will cause the system to write all unflushed data to disk _once
> there's a spinup_.
Yes, I saw that laptop-mode is a nice thing to use, as it tries to combine
both reads and writes in a single operation. Quite neat.
> And I use noflushd with a one-minute spindown time.
Ooops! I just started reading about laptop-mode in the Documentation
directory of the Linux kernel and it says that laptop-mode should not be
used in conjunction with noflushd---it says that laptop-mode should be used
with hdparm instead.
Does anybody else have comments on getting long battery life tweaking the
disk?
Thanks, Rogério.
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