X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.timer.xml;h=bb3a6d138650d18e262a716ed284c7bb8db17802;hp=2c2ba5822653abad5395832b61bace03c6d861c9;hb=89f7c8465cd1ab37347dd0c15920bce31e8225df;hpb=ccc9a4f9ffdab069b0b785627c48962fdadf6d46 diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml index 2c2ba5822..bb3a6d138 100644 --- a/man/systemd.timer.xml +++ b/man/systemd.timer.xml @@ -48,14 +48,14 @@ - systemd.timer + timer.timer Description A unit configuration file whose name ends in - .timer encodes information about + .timer encodes information about a timer controlled and supervised by systemd, for timer-based activation. @@ -128,7 +128,7 @@ combined of the same and of different types. For example, by combining OnBootSec= and - OnUnitActiveSec= it is + OnUnitActiveSec=, it is possible to define a timer that elapses in regular intervals and activates a specific service each @@ -141,7 +141,7 @@ also include time units. Example: "OnBootSec=5h 30min" means 5 hours and 30 minutes after boot-up. For details - about the syntax of time spans see + about the syntax of time spans, see systemd.unit5. If a timer configured with @@ -160,10 +160,17 @@ monotonic clock stops too. If the empty string is assigned - to any of these options the list of + to any of these options, the list of timers is reset, and all prior assignments will have no - effect. + effect. + + Note that timers do not + necessarily expire at the precise + time configured with these settings, + as they are subject to the + AccuracySec= + setting below. @@ -171,23 +178,68 @@ OnCalendar= Defines realtime - (i.e. wallclock) timers via calendar + (i.e. wallclock) timers with calendar event expressions. See systemd.time7 for more information on the syntax of - calendar event expressions. Otherwise + calendar event expressions. Otherwise, the semantics are similar to OnActiveSec= and - related settings. + related settings. + + Note that timers do not + necessarily expire at the precise + time configured with this setting, + as it is subject to the + AccuracySec= + setting below. + + AccuracySec= + + Specify the accuracy + the timer shall elapse with. Defaults + to 1min. The timer is scheduled to + elapse within a time window starting + with the time specified in + OnCalendar=, + OnActiveSec=, + OnBootSec=, + OnStartupSec=, + OnUnitActiveSec= or + OnUnitInactiveSec= + and ending the time configured with + AccuracySec= + later. Within this time window, the + expiry time will be placed at a + host-specific, randomized but stable + position, that is synchronized between + all local timer units. This is done in + order to distribute the wake-up time + in networked installations, as well as + optimizing power consumption to + suppress unnecessary CPU wake-ups. To + get best accuracy, set this option to + 1us. Note that the timer is still + subject to the timer slack configured + via + systemd-system.conf5's + TimerSlackNSec= + setting. See + prctl2 + for details. To optimize power + consumption, make sure to set this + value as high as possible and as low + as necessary. + Unit= The unit to activate when this timer elapses. The argument is a unit name, whose suffix is not - .timer. If not + .timer. If not specified, this value defaults to a service that has the same name as the timer unit, except for the @@ -208,7 +260,9 @@ systemd.unit5, systemd.service5, systemd.time7, - systemd.directives7 + systemd.directives7, + systemd-system.conf5, + prctl2