man: extend a bit what to expect from the various places apps can store data

[elogind.git] / man / systemd.timer.xml

diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml
index 659bc81ccd9d69f2245c6d017b48a6a0687a5d1a..d82b9bdc973b09846231bbef88799a855ab8e557 100644 (file)
--- a/man/systemd.timer.xml
+++ b/man/systemd.timer.xml
@@ -141,7 +141,7 @@
                                 also include time units. Example:
                                 "OnBootSec=5h 30min" means 5 hours and
                                 30 minutes after boot-up. For details
                                 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

                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 
                                 <para>If a timer configured with
                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 
                                 <para>If a timer configured with


@@ -163,7 +163,14 @@
                                 to any of these options, the list of
                                 timers is reset, and all prior
                                 assignments will have no
                                 to any of these options, the list of
                                 timers is reset, and all prior
                                 assignments will have no

-                                effect.</para></listitem>
+                                effect.</para>
+
+                                <para>Note that timers do not
+                                necessarily expire at the precise
+                                time configured with these settings,
+                                as they are subject to the
+                                <varname>AccuracySec=</varname>
+                                setting below.</para></listitem>

 
                         </varlistentry>
 
 
                         </varlistentry>
 


@@ -171,16 +178,61 @@
                                 <term><varname>OnCalendar=</varname></term>
 
                                 <listitem><para>Defines realtime
                                 <term><varname>OnCalendar=</varname></term>
 
                                 <listitem><para>Defines realtime

-                                (i.e. wallclock) timers via calendar
+                                (i.e. wallclock) timers with calendar

                                 event expressions. See
                                 <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                                 for more information on the syntax of
                                 event expressions. See
                                 <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                                 for more information on the syntax of

-                                calendar event expressions. Otherwise
+                                calendar event expressions. Otherwise,

                                 the semantics are similar to
                                 <varname>OnActiveSec=</varname> and
                                 the semantics are similar to
                                 <varname>OnActiveSec=</varname> and

-                                related settings.</para></listitem>
+                                related settings.</para>
+
+                                <para>Note that timers do not
+                                necessarily expire at the precise
+                                time configured with this setting,
+                                as it is subject to the
+                                <varname>AccuracySec=</varname>
+                                setting below.</para></listitem>

                         </varlistentry>
 
                         </varlistentry>
 

+                        <varlistentry>
+                                <term><varname>AccuracySec=</varname></term>
+
+                                <listitem><para>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
+                                <varname>OnCalendar=</varname>,
+                                <varname>OnActiveSec=</varname>,
+                                <varname>OnBootSec=</varname>,
+                                <varname>OnStartupSec=</varname>,
+                                <varname>OnUnitActiveSec=</varname> or
+                                <varname>OnUnitInactiveSec=</varname>
+                                and ending the time configured with
+                                <varname>AccuracySec=</varname>
+                                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
+                                <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s
+                                <varname>TimerSlackNSec=</varname>
+                                setting. See
+                                <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+                                for details. To optimize power
+                                consumption, make sure to set this
+                                value as high as possible and as low
+                                as necessary.</para></listitem>
+                        </varlistentry>

                         <varlistentry>
                                 <term><varname>Unit=</varname></term>
 
                         <varlistentry>
                                 <term><varname>Unit=</varname></term>
 


@@ -197,6 +249,43 @@
                                 are named identically, except for the
                                 suffix.</para></listitem>
                         </varlistentry>
                                 are named identically, except for the
                                 suffix.</para></listitem>
                         </varlistentry>

+
+
+                        <varlistentry>
+                                <term><varname>Persistent=</varname></term>
+
+                                <listitem><para>Takes a boolean
+                                argument. If true, the time when the
+                                service unit was last triggered is
+                                stored on disk. When the timer is
+                                activated, the service unit is
+                                triggered immediately if it would have
+                                been triggered at least once during
+                                the time when the timer was inactive.
+                                This is useful to catch up on missed
+                                runs of the service when the machine
+                                was off. Note that this setting only
+                                has an effect on timers configured
+                                with <varname>OnCalendar=</varname>.
+                                </para></listitem>
+                        </varlistentry>
+
+                        <varlistentry>
+                                <term><varname>WakeSystem=</varname></term>
+
+                                <listitem><para>Takes a boolean
+                                argument. If true, an elapsing timer
+                                will cause the system to resume from
+                                suspend, should it be suspended and if
+                                the system supports this. Note that
+                                this option will only make sure the
+                                system resumes on the appropriate
+                                times, it will not take care of
+                                suspending it again after any work
+                                that is to be done is
+                                finished. Defaults to
+                                <varname>false</varname>.</para></listitem>
+                        </varlistentry>

                 </variablelist>
         </refsect1>
 
                 </variablelist>
         </refsect1>
 


@@ -208,7 +297,9 @@
                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

-                          <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+                          <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>

                   </para>
         </refsect1>
 
                   </para>
         </refsect1>