Fast network resume after sleep; experiments

altercation · 2011-09-10 08:28:38

Is this a terrible idea? I'm going for immediate network resumption without the normal 2-6 second pause after sleep.

http://www.youtube.com/watch?v=DzalQvcgtcM

I've been experimenting with fast sleep/wake. I like and use pm-utils but it's not the fastest and I have a little too much black box feeling when I use it, so I wanted to see how much I could get done just in /etc/acpi/handler.sh . So far I'm pretty happy with the results and sleep/wake are both sub-second, though video resume is the last to kick in so the wake is longer than sleep (not by much, though).

The bigger issue is the notoriously "slow" dhcp address check (see http://cafbit.com/entry/rapid_dhcp_or_how_do for an overview).

I played around with arping in dhcpcd.conf. Interesting and seems like that might have some potential, but my current method seems simpler.

Right now I'm just setting NETWORK_PERSIST in /etc/rc.conf to "yes". There is thus no dhcp check after resume.

I've also stopped unloading the network driver and am just letting the kernel handle the suspend there. So far it works most of the time without error or hiccup (occasionally there is a few second pause).

Question: is this a terrible idea? If so, why? I haven't tested for dhcp lease expiry but I assume at that point there will be a release (dhcpcd is still running normally, it's just the network remains nominally "up" through the suspend/wake cycle).

This is all 3.0-ARCH, all official repos. I wanted to try compat-wireless from AUR but the kernel.org mirrors are still down so will do that later.

Last edited by altercation (2011-09-10 08:29:27)

eldragon · 2011-09-10 12:37:54

use a static ip address

altercation · 2011-09-10 18:37:16

Not really useful with a laptop. This is a roaming machine. Regardless, my question is about DHCP based network resumption specifically (see the second link in the original post for details). I do use static addresses on my desktop and fixed location machines.

To clarify my question: is using NETWORK_PERSIST="yes" a bad idea in this laptop sleep/wake scenario? It seems like a *good* idea in that it avoids the lease rebinding. It makes me wonder why it isn't a standard recommendation... what problems can it create, if any?

Last edited by altercation (2011-09-10 18:38:33)

Arch Linux

#1 2011-09-10 08:28:38

Fast network resume after sleep; experiments

#2 2011-09-10 12:37:54

Re: Fast network resume after sleep; experiments

#3 2011-09-10 18:37:16

Re: Fast network resume after sleep; experiments

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