core: add SoftRebootStartTimestamp

Will be useful to calculate how long it took to shut down the system before starting
in the new root

man/org.freedesktop.systemd1.xml

@@ -340,6 +340,10 @@ node /org/freedesktop/systemd1 {
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly t FinishTimestampMonotonic = ...;
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+      readonly t SoftRebootStartTimestamp = ...;
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+      readonly t SoftRebootStartTimestampMonotonic = ...;
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly t SecurityStartTimestamp = ...;
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly t SecurityStartTimestampMonotonic = ...;
@@ -1033,6 +1037,10 @@ node /org/freedesktop/systemd1 {
 
     <variablelist class="dbus-property" generated="True" extra-ref="FinishTimestampMonotonic"/>
 
+    <variablelist class="dbus-property" generated="True" extra-ref="SoftRebootStartTimestamp"/>
+
+    <variablelist class="dbus-property" generated="True" extra-ref="SoftRebootStartTimestampMonotonic"/>
+
     <variablelist class="dbus-property" generated="True" extra-ref="SecurityStartTimestamp"/>
 
     <variablelist class="dbus-property" generated="True" extra-ref="SecurityStartTimestampMonotonic"/>
@@ -1733,17 +1741,19 @@ node /org/freedesktop/systemd1 {
       <varname>KernelTimestamp</varname>, <varname>KernelTimestampMonotonic</varname>,
       <varname>InitRDTimestamp</varname>, <varname>InitRDTimestampMonotonic</varname>,
       <varname>UserspaceTimestamp</varname>, <varname>UserspaceTimestampMonotonic</varname>,
-      <varname>FinishTimestamp</varname>, and <varname>FinishTimestampMonotonic</varname> encode
+      <varname>FinishTimestamp</varname>, <varname>FinishTimestampMonotonic</varname>,
-      <constant>CLOCK_REALTIME</constant> and <constant>CLOCK_MONOTONIC</constant> microsecond timestamps
+      <varname>SoftRebootStartTimestamp</varname> and <varname>SoftRebootStartTimestampMonotonic</varname>
-      taken when the firmware first began execution, when the boot loader first began execution, when the
+      encode <constant>CLOCK_REALTIME</constant> and <constant>CLOCK_MONOTONIC</constant> microsecond
-      kernel first began execution, when the initrd first began execution, when the main systemd instance
+      timestamps taken when the firmware first began execution, when the boot loader first began execution,
-      began execution and finally, when all queued startup jobs finished execution. These values are useful
+      when the kernel first began execution, when the initrd first began execution, when the main systemd
-      for determining boot-time performance. Note that as monotonic time begins with the kernel startup, the
+      instance began execution, when all queued startup jobs finished execution and finally, when a
-      <varname>KernelTimestampMonotonic</varname> timestamp will always be 0 and
+      <citerefentry><refentrytitle>systemd-soft-reboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-      <varname>FirmwareTimestampMonotonic</varname> and <varname>LoaderTimestampMonotonic</varname> are to
+      operation first began execution. These values are useful for determining boot-time performance. Note
-      be read as negative values. Also, not all fields are always available, depending on the used firmware,
+      that as monotonic time begins with the kernel startup, the <varname>KernelTimestampMonotonic</varname>
-      boot loader or initrd implementation. In these cases the respective pairs of timestamps are both 0,
+      timestamp will always be 0 and <varname>FirmwareTimestampMonotonic</varname> and
-      indicating that no data is available.</para>
+      <varname>LoaderTimestampMonotonic</varname> are to be read as negative values. Also, not all fields
+      are always available, depending on the used firmware, boot loader or initrd implementation. In these
+      cases the respective pairs of timestamps are both 0, indicating that no data is available.</para>
 
       <para><varname>UnitsLoadTimestamp</varname> and <varname>UnitsLoadTimestampMonotonic</varname> encode
       <constant>CLOCK_REALTIME</constant> and <constant>CLOCK_MONOTONIC</constant> microseconds timestamps
@@ -11982,7 +11992,9 @@ $ gdbus introspect --system --dest org.freedesktop.systemd1 \
       <function>QueueSignalUnit()</function>,
       <function>SoftReboot()</function>, and
       <function>DumpUnitFileDescriptorStore()</function> were added in version 254.</para>
-      <para><function>StartAuxiliaryScope()</function> was added in version 256.</para>
+      <para><function>StartAuxiliaryScope()</function>,
+      <varname>SoftRebootStartTimestamp</varname> and
+      <varname>SoftRebootStartTimestampMonotonic</varname> were added in version 256.</para>
     </refsect2>
     <refsect2>
       <title>Unit Objects</title>

src/core/dbus-manager.c

@@ -3042,6 +3042,7 @@ const sd_bus_vtable bus_manager_vtable[] = {
         BUS_PROPERTY_DUAL_TIMESTAMP("InitRDTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_INITRD]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("UserspaceTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_USERSPACE]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("FinishTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_FINISH]), SD_BUS_VTABLE_PROPERTY_CONST),
+        BUS_PROPERTY_DUAL_TIMESTAMP("SoftRebootStartTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_SOFTREBOOT_START]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("SecurityStartTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_SECURITY_START]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("SecurityFinishTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_SECURITY_FINISH]), SD_BUS_VTABLE_PROPERTY_CONST),
         BUS_PROPERTY_DUAL_TIMESTAMP("GeneratorsStartTimestamp", offsetof(Manager, timestamps[MANAGER_TIMESTAMP_GENERATORS_START]), SD_BUS_VTABLE_PROPERTY_CONST),

src/core/main.c

@@ -2129,6 +2129,8 @@ static int invoke_main_loop(
                         manager_send_reloading(m);
                         manager_set_switching_root(m, true);
 
+                        dual_timestamp_now(m->timestamps + MANAGER_TIMESTAMP_SOFTREBOOT_START);
+
                         r = prepare_reexecute(m, &arg_serialization, ret_fds, /* switching_root= */ true);
                         if (r < 0) {
                                 *ret_error_message = "Failed to prepare for reexecution";

src/core/manager.c

@@ -3694,7 +3694,17 @@ static void manager_notify_finished(Manager *m) {
         if (MANAGER_IS_TEST_RUN(m))
                 return;
 
-        if (MANAGER_IS_SYSTEM(m) && detect_container() <= 0) {
+        if (MANAGER_IS_SYSTEM(m) && dual_timestamp_is_set(&m->timestamps[MANAGER_TIMESTAMP_SOFTREBOOT_START])) {
+                /* The soft-reboot case, where we only report data for the last reboot */
+                firmware_usec = loader_usec = initrd_usec = kernel_usec = 0;
+                total_usec = userspace_usec = m->timestamps[MANAGER_TIMESTAMP_FINISH].monotonic - m->timestamps[MANAGER_TIMESTAMP_SOFTREBOOT_START].monotonic;
+
+                log_struct(LOG_INFO,
+                           "MESSAGE_ID=" SD_MESSAGE_STARTUP_FINISHED_STR,
+                           "USERSPACE_USEC="USEC_FMT, userspace_usec,
+                           LOG_MESSAGE("Soft-reboot finished in %s.",
+                                       FORMAT_TIMESPAN(total_usec, USEC_PER_MSEC)));
+        } else if (MANAGER_IS_SYSTEM(m) && detect_container() <= 0) {
                 char buf[FORMAT_TIMESPAN_MAX + STRLEN(" (firmware) + ") + FORMAT_TIMESPAN_MAX + STRLEN(" (loader) + ")]
                         = {};
                 char *p = buf;
@@ -5041,6 +5051,7 @@ static const char *const manager_timestamp_table[_MANAGER_TIMESTAMP_MAX] = {
         [MANAGER_TIMESTAMP_INITRD]                   = "initrd",
         [MANAGER_TIMESTAMP_USERSPACE]                = "userspace",
         [MANAGER_TIMESTAMP_FINISH]                   = "finish",
+        [MANAGER_TIMESTAMP_SOFTREBOOT_START]         = "softreboot-start",
         [MANAGER_TIMESTAMP_SECURITY_START]           = "security-start",
         [MANAGER_TIMESTAMP_SECURITY_FINISH]          = "security-finish",
         [MANAGER_TIMESTAMP_GENERATORS_START]         = "generators-start",

src/core/manager.h

@@ -120,6 +120,9 @@ typedef enum ManagerTimestamp {
         MANAGER_TIMESTAMP_INITRD_GENERATORS_FINISH,
         MANAGER_TIMESTAMP_INITRD_UNITS_LOAD_START,
         MANAGER_TIMESTAMP_INITRD_UNITS_LOAD_FINISH,
+
+        MANAGER_TIMESTAMP_SOFTREBOOT_START,
+
         _MANAGER_TIMESTAMP_MAX,
         _MANAGER_TIMESTAMP_INVALID = -EINVAL,
 } ManagerTimestamp;