[systemd-devel] idle daemon sleep

[Alexandre Detiste]

Le mercredi 31 décembre 2014, 08:23:51 Mantas Mikulėnas a écrit :
> Even for .timer units, systemd simply sleeps until it's actually time
> for the next event – like cron, or Task Scheduler for that matter.
> There shouldn't be any "is it time yet?".

In fact, many people complain that cron does wakes up their laptop every minute;
and that increase battery consumption, while systemd timers doesn't suffer from this.

http://unixhelp.ed.ac.uk/CGI/man-cgi?crond
[ Additionally,  cron  checks each minute to see if its spool directory's
[ modtime (or the modtime on /etc/crontab) has changed

http://content.hccfl.edu/pollock/unix/crontab.htm
[ Each minute the cron daemon wakes up and compares the crontab file entries against the current time.
[ If the five fields match the current minute then the command is executed.