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-rw-r--r--TODO2
-rw-r--r--man/systemd.timer.xml62
-rw-r--r--src/core/dbus-timer.c1
-rw-r--r--src/core/load-fragment-gperf.gperf.m41
-rw-r--r--src/core/timer.c12
-rw-r--r--src/core/timer.h2
-rw-r--r--units/systemd-readahead-done.timer1
7 files changed, 71 insertions, 10 deletions
diff --git a/TODO b/TODO
index f84a24727b..04d92aba03 100644
--- a/TODO
+++ b/TODO
@@ -466,8 +466,6 @@ Features:
* deal with sendmail/postfix exclusivity
* timer units:
- - configurable jitter for timer events
- - Adjust timers to be triggered at the same time as sd-event timers
- timer events with system resume
- timer units should get the ability to trigger when:
o CLOCK_REALTIME makes jumps (TFD_TIMER_CANCEL_ON_SET)
diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml
index 659bc81ccd..484287ccf6 100644
--- a/man/systemd.timer.xml
+++ b/man/systemd.timer.xml
@@ -163,7 +163,14 @@
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 are not
+ necessarily expired at the precise
+ time configured with these settings,
+ as they are subject to the
+ <varname>AccuracySec=</varname>
+ setting below.</para></listitem>
</varlistentry>
@@ -171,17 +178,62 @@
<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
calendar event expressions. Otherwise
the semantics are similar to
<varname>OnActiveSec=</varname> and
- related settings.</para></listitem>
+ related settings.</para>
+
+ <para>Note that timers are not
+ necessarily expired at the precise
+ time configured with this setting,
+ as it is subject to the
+ <varname>AccuracySec=</varname>
+ setting below.</para></listitem>
</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
+ expire 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>
<listitem><para>The unit to activate
@@ -208,7 +260,9 @@
<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.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>
diff --git a/src/core/dbus-timer.c b/src/core/dbus-timer.c
index 9e4070a1a3..b7155219ef 100644
--- a/src/core/dbus-timer.c
+++ b/src/core/dbus-timer.c
@@ -143,6 +143,7 @@ const sd_bus_vtable bus_timer_vtable[] = {
SD_BUS_PROPERTY("NextElapseUSecRealtime", "t", bus_property_get_usec, offsetof(Timer, next_elapse_monotonic), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("NextElapseUSecMonotonic", "t", bus_property_get_usec, offsetof(Timer, next_elapse_realtime), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Result", "s", property_get_result, offsetof(Timer, result), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("AccuracyUSec", "t", bus_property_get_usec, offsetof(Timer, accuracy_usec), 0),
SD_BUS_VTABLE_END
};
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index 22dc536ee1..fbf8381bc1 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -247,6 +247,7 @@ Timer.OnBootSec, config_parse_timer, 0,
Timer.OnStartupSec, config_parse_timer, 0, 0
Timer.OnUnitActiveSec, config_parse_timer, 0, 0
Timer.OnUnitInactiveSec, config_parse_timer, 0, 0
+Timer.AccuracySec, config_parse_sec, 0, offsetof(Timer, accuracy_usec)
Timer.Unit, config_parse_trigger_unit, 0, 0
m4_dnl
Path.PathExists, config_parse_path_spec, 0, 0
diff --git a/src/core/timer.c b/src/core/timer.c
index 5bc01a26ff..f23582c2db 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -47,6 +47,7 @@ static void timer_init(Unit *u) {
t->next_elapse_monotonic = (usec_t) -1;
t->next_elapse_realtime = (usec_t) -1;
+ t->accuracy_usec = USEC_PER_MINUTE;
}
void timer_free_values(Timer *t) {
@@ -144,6 +145,7 @@ static int timer_load(Unit *u) {
}
static void timer_dump(Unit *u, FILE *f, const char *prefix) {
+ char buf[FORMAT_TIMESPAN_MAX];
Timer *t = TIMER(u);
Unit *trigger;
TimerValue *v;
@@ -153,10 +155,12 @@ static void timer_dump(Unit *u, FILE *f, const char *prefix) {
fprintf(f,
"%sTimer State: %s\n"
"%sResult: %s\n"
- "%sUnit: %s\n",
+ "%sUnit: %s\n"
+ "%sAccuracy: %s\n",
prefix, timer_state_to_string(t->state),
prefix, timer_result_to_string(t->result),
- prefix, trigger ? trigger->id : "n/a");
+ prefix, trigger ? trigger->id : "n/a",
+ prefix, format_timespan(buf, sizeof(buf), t->accuracy_usec, 1));
LIST_FOREACH(value, v, t->values) {
@@ -346,7 +350,7 @@ static void timer_enter_waiting(Timer *t, bool initial) {
r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_ONESHOT);
} else
- r = sd_event_add_monotonic(UNIT(t)->manager->event, t->next_elapse_monotonic, 0, timer_dispatch, t, &t->monotonic_event_source);
+ r = sd_event_add_monotonic(UNIT(t)->manager->event, t->next_elapse_monotonic, t->accuracy_usec, timer_dispatch, t, &t->monotonic_event_source);
if (r < 0)
goto fail;
@@ -372,7 +376,7 @@ static void timer_enter_waiting(Timer *t, bool initial) {
r = sd_event_source_set_enabled(t->realtime_event_source, SD_EVENT_ONESHOT);
} else
- r = sd_event_add_realtime(UNIT(t)->manager->event, t->next_elapse_realtime, 0, timer_dispatch, t, &t->realtime_event_source);
+ r = sd_event_add_realtime(UNIT(t)->manager->event, t->next_elapse_realtime, t->accuracy_usec, timer_dispatch, t, &t->realtime_event_source);
if (r < 0)
goto fail;
diff --git a/src/core/timer.h b/src/core/timer.h
index b3722f0028..3e7efa4c83 100644
--- a/src/core/timer.h
+++ b/src/core/timer.h
@@ -69,6 +69,8 @@ typedef enum TimerResult {
struct Timer {
Unit meta;
+ usec_t accuracy_usec;
+
LIST_HEAD(TimerValue, values);
usec_t next_elapse_monotonic;
usec_t next_elapse_realtime;
diff --git a/units/systemd-readahead-done.timer b/units/systemd-readahead-done.timer
index 41bfb2bd32..bdfd465913 100644
--- a/units/systemd-readahead-done.timer
+++ b/units/systemd-readahead-done.timer
@@ -15,6 +15,7 @@ Before=shutdown.target
[Timer]
OnActiveSec=30s
+AccuracySec=1s
[Install]
Also=systemd-readahead-collect.service
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-04 06:30:46 +0000