X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.timer.xml;h=484287ccf67fc3f770f6883e8f7df6039e8b4d3e;hp=e08e20021252a7f1bb0e04fb6a9bba9841ab1dcb;hb=85feb8e4d9b0ef65c338e1a1a16665d0cb8d544a;hpb=9cc2c8b763fb4b9ddda95756a727a438a0d2a012
diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml
index e08e20021..484287ccf 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.
@@ -97,7 +97,7 @@
defines. The options specific to the [Timer] section
of timer units are the following:
-
+
OnActiveSec=
OnBootSec=
@@ -115,7 +115,7 @@
machine was booted
up. OnStartupSec=
defines a timer relative to when
- systemd was
+ systemd was first
started. OnUnitActiveSec=
defines a timer relative to when the
unit the timer is activating was last
@@ -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
@@ -157,7 +157,20 @@
These are monotonic timers,
independent of wall-clock time and timezones. If the
computer is temporarily suspended, the
- monotonic clock stops too.
+ monotonic clock stops too.
+
+ If the empty string is assigned
+ to any of these options, the list of
+ timers is reset, and all prior
+ assignments will have no
+ effect.
+
+ Note that timers are not
+ necessarily expired at the precise
+ time configured with these settings,
+ as they are subject to the
+ AccuracySec=
+ setting below.
@@ -165,21 +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.
+ calendar event expressions. Otherwise
+ the semantics are similar to
+ OnActiveSec= and
+ related settings.
+
+ Note that timers are not
+ necessarily expired 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
+ expire 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
@@ -200,7 +260,9 @@
systemd.unit5,
systemd.service5,
systemd.time7,
- systemd.directives7
+ systemd.directives7,
+ systemd-system.conf5,
+ prctl2