LPC: Booting Linux in five seconds

Posted Sep 22, 2008 23:20 UTC (Mon) by nix (subscriber, #2304)
In reply to: LPC: Booting Linux in five seconds by anselm
Parent article: LPC: Booting Linux in five seconds

Your applications might have nonpersistent state you want to preserve.

LPC: Booting Linux in five seconds

Posted Sep 22, 2008 23:49 UTC (Mon) by anselm (subscriber, #2796) [Link] (7 responses)

That's what I used to think, too. Nowadays most of my applications do a reasonable job of coming up again where I left them before a shutdown, so it's not a big deal.

LPC: Booting Linux in five seconds

Posted Sep 23, 2008 0:26 UTC (Tue) by rlk (guest, #47505) [Link] (4 responses)

Emacs doesn't; shell buffers and xterms certainly don't have all their state preserved (possibly megabytes of output, and yes, I do care about that). Much less any background processes I happen to have left running actively (Gutenprint tests, for example).

As I said previously, fast reboot and suspend/resume solve different problems and shouldn't be considered alternatives for each other.

That could be fixed

Posted Sep 23, 2008 1:12 UTC (Tue) by JoeBuck (subscriber, #2330) [Link] (3 responses)

It would be possible to make Emacs session-aware.

That could be fixed

Posted Sep 23, 2008 7:29 UTC (Tue) by nix (subscriber, #2304) [Link] (2 responses)

You'd need to modify a good bit of Lisp (at least you'd need to think of
something to do with process sentinels).

Hm, perhaps a shutdown/restart could appear to the Lisp code like all the
process sentinels signalling a process death/network disconnection,
something they have to deal with anyway... obviously you'd also want a
session-save-hook and session-restore-hook, so that things that *want* to
be aware of shutdown/restart can be. (And let's implement it with proper
serialization/deserialization of the in-core Lisp state, not with
unexec()! :) )

That could be fixed

Posted Sep 23, 2008 15:00 UTC (Tue) by shapr (subscriber, #9077) [Link] (1 responses)

What about emacs desktop? I've been using that for years.
Right now emacs does not save the state of all the open buffers etc until I explicitly exit, but if it saved every minute or so even crashes would have most session state saved.

That could be fixed

Posted Sep 23, 2008 15:14 UTC (Tue) by rlk (guest, #47505) [Link]

The issue isn't just open file buffers:

* Shell buffers (input and output history -- including input and output history of the shell, which isn't quite the same thing as the emacs idea of that)

* Command output buffers and other temporary buffers, including *scratch*

* Files that you're looking at that may get changed behind your back that you deliberately haven't reverted yet.

* The state of the lisp world

Obviously, emacs loses all of this if it crashes, but this in the context of choosing to reboot vs. suspend/resume. I'll take my chances on crashes, and I do save my work, but it's still more efficient to keep a session going as long as possible.

LPC: Booting Linux in five seconds

Posted Sep 23, 2008 7:54 UTC (Tue) by mjthayer (guest, #39183) [Link] (1 responses)

> Nowadays most of my applications do a reasonable job of coming up again
> where I left them before a shutdown, so it's not a big deal.

But they can take an awful long time to do so. Don't know if suspend/resume is faster, because I have never trusted it enough to find out. Perhaps a middle way would be best of all - suspending and resuming individual applications, perhaps even with the application's cooperation.

LPC: Booting Linux in five seconds

Posted Sep 23, 2008 8:23 UTC (Tue) by mjthayer (guest, #39183) [Link]

Ahem, actually exactly what ebirdie said in a comment further up.