F-16 suspends my *desktop* after 30 minutes at the gdm , making it impossible to ssh in

Martin Langhoff martin.langhoff at gmail.com
Mon Oct 3 14:12:25 UTC 2011

On Sun, Oct 2, 2011 at 4:13 PM, Jason D. Clinton <me at jasonclinton.com> wrote:
>> 2) The machine has a server function. In this case working wake on lan and
>>    stay active on lan are a must have and until we have those it should not
>>    auto suspend.
> WOL for a network server is madness. It shouldn't have been suggested.

Well, it's not well supported now across the stack, but it is surely
not madness.

On the XO hardware we actually use WOL while there peer-to-peer
network connections up. On x86 the wakeup time is not so good. On the
upcoming ARM model, the wakeup time is expected to be very low. We are
sorting out wakeup right now so can't really say, but surely <100ms.

This means that blade servers running ARM (or any SoC where power mgmt
has been well designed) can be drawing ~250mw in a suspend that looks
a lot like a very deep sleep. No fans, no "aircon footprint".

Are there things to resolve on the way to making this practical? Definitely!

Should we be riding the "I want lower power draw / fast+transparent
suspend/deep-idle on my netbook" wave to benefit the server space? I
sure think so.

> A fully power-saved Sandy Bridge laptop in the state you lay out above
> is around 7W. A suspended laptop from the same generation consumes
> roughly 0.4W of power. Stand-by is 0.1W.

Interesting numbers. The big questions is -- does it suspend and
resume fast and transparently enough that you can treat suspend as a
"very deep idle"?

And how fast can we bring those improvements to the much bigger
numbers you have for servers.

 martin.langhoff at gmail.com
 martin at laptop.org -- Software Architect - OLPC
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first
 - http://wiki.laptop.org/go/User:Martinlanghoff

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