Messages in this thread | | | Date | Tue, 09 Oct 2007 01:08:24 -0400 | From | Chris Snook <> | Subject | Re: gigabit ethernet power consumption |
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Pavel Machek wrote: > Hi! > > I've found that gbit vs. 100mbit power consumption difference is about > 1W -- pretty significant. (Maybe powertop should include it in the > tips section? :). > > Energy Star people insist that machines should switch down to 100mbit > when network is idle, and I guess that makes a lot of sense -- you > save 1W locally and 1W on the router. > > Question is, how to implement it correctly? Daemon that would watch > data rates and switch speeds using mii-tool would be simple, but is > that enough?
I believe you misspelled "ethtool".
While you're at it, why stop at 100Mb? I believe you save even more power at 10Mb, which is why WOL puts the card in 10Mb mode. In my experience, you generally want either the maximum setting or the minimum setting when going for power savings, because of the race-to-idle effect. Workloads that have a sustained fractional utilization are rare. Right now I'm at home, hooked up to a cable modem, so anything over 4Mb is wasted, unless I'm talking to the box across the room, which is rare.
Talk to the NetworkManager folks. This is right up their alley.
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