[maemo-developers] suspendprocess - poor man's power save

[From: Eero Tamminen]

Hi,

ext Andrew Flegg wrote:
> On Sun, Sep 19, 2010 at 17:58, Robin Burchell <viroteck at viroteck.net> wrote:
>> Anyway: this was pretty much in keeping with my idea: move it into the task
>> switcher (hildon-desktop/other) so that applications which are moved to
>> background are stopped (unless they signal for whatever reason that they
>> need to be kept running, but I'm not even sure that is necessary: if
>> you really need to do background processing constantly, why do it in a
>> GUI application?)
> 
> I suggested something similar three years ago (wow, Maemo's old ;-))
> and the reaction was less favourable:
> 
>     http://www.gossamer-threads.com/lists/maemo/users/26337
> 
> For example, Igor Stoppa wrote:
>> You are proposing a shortcut that is encouraging crappy code to be
>> written, since the system will always take care of saying: "psst,
>> pretend to be a properly written piece of code".
>>
>> If an application has nothing to do, it _must_ be blocked waiting for
>> something, such as an event, a timer, whatever it cares about, nothing
>> else.
> 
> Personally, I think it'd still be useful; without going to the
> (almost) co-operative multi-tasking of iOS.

There are some potential downsides for just suspending processes
completely.  Most of the processes have subscribed to several
different D-BUS messages, X events etc.

For example D-BUS will infinitely buffer messages that are sent
to a connected client but not read by it.  If these messages can
be very frequent (say device orientation & network condition messages),
this will soon bloat D-BUS memory usage quite a bit.  After D-BUS
starts to swap, it won't perform very well.

These kind of services cannot be restarted without restarting the whole
device (as all connected clients would exit), so there's no easy fix for
that effect either, like there's for example for a leaky in-process
3rd party Home applet (restarting Home).


	- Eero