Trying to reduce our memory and battery footprint

[Martin Pitt]

Hello all,

Ted Gould [2012-10-16 15:06 -0500]:
> So then can we really early (right now) rearrange the desktop startup to
> start upstart when then start dbus and gnome-session?  That would give
> us the ability to start migrating jobs over to being upstart user jobs
> over time without having to do all at once (like we have done with SysV
> Init jobs in system startup).

Not wanting to spoil the show, but before we make the desktop startup
dependent on more Ubuntu-only technology: Is that really what we need
here? I don't think the reason why starting Unity and starting the
Dash takes so long is in any way related to startup order or that we
wouldn't have a mechanism of starting things on demand (D-Bus
activation works just fine for the most part).

From what I can see, it's because Unity accepted one Python daemon
after the other, compiz' architecture (fine-grained plugins, lots
of XML parsing, inability to statically link to common plugins, etc)
takes a high toll, and indicators/global menu is very chatty on the
D-Bus (that alone takes ~ 1 second on an Atom CPU when e. g. starting
nautilus!).

I. e. when boot speed and memory consumption are really an issue, I'm
afraid we actually need to reeinginer those things again; Using
upstart won't help there.

One opportunity where having session upstart (or systemd, FWIW) jobs
would be handy is to finally replace update-notifier. It's become a
collection of totally unrelated things (launching update-manager,
launching Apport on crashes, launching Jockey on missing firmware,
etc) just because we always need a session daemon to listen for
events. This could be replaced by individual jobs that are triggered
by uevents and inotify watches. This will help maintainability and
improve memory usage a bit (2.5 MB RSS for upstart vs. 13 MB RSS
update-notifier), and shouldn't noticeably increase CPU overhead.

Do you have other cases in mind which would benefit from this?

Thanks,

Martin

-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)
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