[systemd-devel] [RFC] core: introduce ExitOnIdle= and ExitOnIdleSec=

[Umut Tezduyar Lindskog]

My two cents is feature can be implemented as long as we get support
from the application. For example sd-event has the builtin support to
quit when it is idle. Systemd can pass the exit-on-idle timeout to the
application via env variables so the event loop can configure itself
to quit.

I am not sure if glib event loop has this functionality already but I
would be very interested to have it. I am just waiting for kdbus.
Exiting on non-kdbus is still racy if we don't let systemd know
upfront.

Umut

On Mon, Apr 20, 2015 at 5:10 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Mon, 20.04.15 23:56, WaLyong Cho (walyong.cho at samsung.com) wrote:
>
>> If a service does not consume CPU during some time(can be configured
>> by ExitOnIdleSec=) and set to stopped on idle state(ExitOnIdle=), the
>> service will be stopped. This can be useful if the service provides
>> some of activation methods.
>
> Hmm, I am not convinced this would be a good idea, sorry.
>
> The crux of the issue is that it is really hard to detect from the
> outside if a daemon is really idle. Only the daemon itself knows
> whether it is truly idle or not. I mean, it could just be waiting for
> some timer to elapse, or some other external event.
>
> I doubt this is really useful unless you have really really simple
> daemons that purely react on client requests and nothing else, and you
> know the codebase and that it is OK to terminate the daemon just
> because its CPU usage is zero. But if you know the codebase that well
> it would probably be a better idea to just add support for
> exit-on-idle directly to the daemon in question.
>
> exit-on-idle is really something that should be implemented *in* the
> daemon, and not done externally!
>
> Sorry,
>
> Lennart
>
> --
> Lennart Poettering, Red Hat
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