On Tue, 19 Jun 2007, Heikki Linnakangas wrote:

Simon Riggs wrote:
Laptop mode? Linux has it...

Granted, though you're still going to wake up every second, so I'm not sure how much it helps with battery life.

In this context, Linux's laptop mode is all about keeping the disks from spinning up any more than they have to; the fact that the CPU does a little something occasionally isn't so important. I don't think that's an argument for keeping the current range for this parameter though. The goal for a proper laptop mode tuning is for the hard drive to go minutes at a time between waking, and whether bgwriter_delay is 1s or 10s really isn't that big of a difference relative to that scale. Unless you dirty a lot of memory, the laptop mode tuning is going to cache all the writes anyway until it hits the interval where it wakes the disk to catch up.

I can't think of any good reason why the bgwriter_delay can't be reduced to 1s if that simplifies things. You'd need a pretty old system for a longer delay than that to be appropriate.

* Greg Smith [EMAIL PROTECTED] http://www.gregsmith.com Baltimore, MD

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