Revert "Revert "Balder/enforce system time for snapshot""

11 files changed, 125 insertions, 121 deletions

diff --git a/metrics/src/tests/metricmanagertest.cpp b/metrics/src/tests/metricmanagertest.cpp
index 6d6f21ea7b0..e398e252a36 100644
--- a/metrics/src/tests/metricmanagertest.cpp
+++ b/metrics/src/tests/metricmanagertest.cpp
@@ -29,7 +29,7 @@ struct MetricManagerTest : public ::testing::Test {
     // MetricManager that aren't accessible to "freestanding" fixtures. So we
     // get the test to do the necessary poking and prodding for us instead.
     void takeSnapshots(MetricManager& mm, time_t timeToProcess) {
-        mm.takeSnapshots(mm.getMetricLock(), timeToProcess);
+        mm.takeSnapshots(mm.getMetricLock(), system_time(vespalib::from_s(timeToProcess)));
     }
 };
 
@@ -547,7 +547,7 @@ TEST_F(MetricManagerTest, test_snapshots)
     ASSERT_VALUES(mm,  0 * 60, "6,5,5,2,8,11,2,2,10,3,13");
 
     // Test that reset works
-    mm.reset(1000);
+    mm.reset(system_time(1000s));
     ASSERT_VALUES(mm,      -1, "0,0,0,0,0,0,0,0,0,0,0");
     ASSERT_VALUES(mm,  5 * 60, "0,0,0,0,0,0,0,0,0,0,0");
     ASSERT_VALUES(mm, 60 * 60, "0,0,0,0,0,0,0,0,0,0,0");
@@ -902,7 +902,7 @@ TEST_F(MetricManagerTest, test_text_output)
                       "consumer[1].tags[1]\n"
                       "consumer[1].tags[0] snaptest\n"));
     std::string expected(
-        "snapshot \"Active metrics showing updates since last snapshot\" from 1000 to 0 period 0\n"
+        "snapshot \"Active metrics showing updates since last snapshot\" from 1970-01-01 00:16:40.000 UTC to 1970-01-01 00:00:00.000 UTC period 0\n"
         "temp.val6 average=2 last=2 min=2 max=2 count=1 total=2\n"
         "temp.sub.val1 average=4 last=4 min=4 max=4 count=1 total=4\n"
         "temp.sub.valsum average=4 last=4 min=4 max=4 count=1 total=4\n"
@@ -938,11 +938,9 @@ TEST_F(MetricManagerTest, text_output_supports_dimensions)
     fixture.takeSnapshotsOnce();
     std::string actual = fixture.renderLastSnapshotAsText("outer.*temp.*val");
     std::string expected(
-            "snapshot \"5 minute\" from 1000 to 1300 period 300\n"
-            "outer{fancy:stuff}.temp{bar:hyperbar,foo:megafoo}.val1 "
-                "average=2 last=2 min=2 max=2 count=1 total=2\n"
-            "outer{fancy:stuff}.temp{bar:hyperbar,foo:megafoo}.val2"
-                "{baz:superbaz} count=1");
+            "snapshot \"5 minute\" from 1970-01-01 00:16:40.000 UTC to 1970-01-01 00:21:40.000 UTC period 300\n"
+            "outer{fancy:stuff}.temp{bar:hyperbar,foo:megafoo}.val1 average=2 last=2 min=2 max=2 count=1 total=2\n"
+            "outer{fancy:stuff}.temp{bar:hyperbar,foo:megafoo}.val2{baz:superbaz} count=1");
     EXPECT_EQ(expected, actual);
 }
 
diff --git a/metrics/src/tests/summetrictest.cpp b/metrics/src/tests/summetrictest.cpp
index 09495ff038d..8e988b65b96 100644
--- a/metrics/src/tests/summetrictest.cpp
+++ b/metrics/src/tests/summetrictest.cpp
@@ -104,8 +104,7 @@ TEST(SumMetricTest, test_remove)
 TEST(SumMetricTest, test_start_value)
 {
     MetricSnapshot snapshot("active");
-    SumMetric<LongValueMetric> sum("foo", {}, "foodesc",
-                                   &snapshot.getMetrics());
+    SumMetric<LongValueMetric> sum("foo", {}, "foodesc", &snapshot.getMetrics());
     LongValueMetric start("start", {}, "", 0);
     start.set(50);
     sum.setStartValue(start);
@@ -115,7 +114,7 @@ TEST(SumMetricTest, test_start_value)
 
     MetricSnapshot copy("copy");
     copy.recreateSnapshot(snapshot.getMetrics(), true);
-    snapshot.addToSnapshot(copy, 100);
+    snapshot.addToSnapshot(copy, system_time(100s));
 
     LongValueMetric value("value", {}, "", &snapshot.getMetrics());
     sum.addMetricToSum(value);
diff --git a/metrics/src/vespa/metrics/jsonwriter.cpp b/metrics/src/vespa/metrics/jsonwriter.cpp
index c0d227b8f5a..0c9ed306ec9 100644
--- a/metrics/src/vespa/metrics/jsonwriter.cpp
+++ b/metrics/src/vespa/metrics/jsonwriter.cpp
@@ -23,8 +23,8 @@ JsonWriter::visitSnapshot(const MetricSnapshot& snapshot)
 {
     _stream << Object()
         << "snapshot" << Object()
-            << "from" << snapshot.getFromTime()
-            << "to" << snapshot.getToTime()
+            << "from" << vespalib::count_s(snapshot.getFromTime().time_since_epoch())
+            << "to" << vespalib::count_s(snapshot.getToTime().time_since_epoch())
         << End()
         << "values" << Array();
     _flag = SNAPSHOT_STARTED;
diff --git a/metrics/src/vespa/metrics/metricmanager.cpp b/metrics/src/vespa/metrics/metricmanager.cpp
index df83001a4e2..52dca20694f 100644
--- a/metrics/src/vespa/metrics/metricmanager.cpp
+++ b/metrics/src/vespa/metrics/metricmanager.cpp
@@ -28,6 +28,7 @@ using vespalib::make_string_short::fmt;
 using vespalib::count_ms;
 using vespalib::count_s;
 using vespalib::from_s;
+using vespalib::to_string;
 
 MetricManager::ConsumerSpec::ConsumerSpec() = default;
 MetricManager::ConsumerSpec::~ConsumerSpec() = default;
@@ -464,9 +465,9 @@ MetricManager::configure(const MetricLockGuard & , std::unique_ptr<Config> confi
         LOG(debug, "Initializing snapshots as this is first configure call");
         std::vector<SnapSpec> snapshotPeriods(createSnapshotPeriods(*config));
 
-            // Set up snapshots only first time. We don't allow live reconfig
-            // of snapshot periods.
-        time_t currentTime = count_s(_timer->getTime().time_since_epoch());
+        // Set up snapshots only first time. We don't allow live reconfig
+        // of snapshot periods.
+        time_point currentTime = _timer->getTime();
         _activeMetrics.setFromTime(currentTime);
         uint32_t count = 1;
         for (uint32_t i = 0; i< snapshotPeriods.size(); ++i) {
@@ -482,7 +483,7 @@ MetricManager::configure(const MetricLockGuard & , std::unique_ptr<Config> confi
                     _activeMetrics.getMetrics(), _snapshotUnsetMetrics));
             count = nextCount;
         }
-            // Add all time snapshot.
+        // Add all time snapshot.
         _totalMetrics = std::make_shared<MetricSnapshot>("All time snapshot", 0, _activeMetrics.getMetrics(), _snapshotUnsetMetrics);
         _totalMetrics->reset(currentTime);
     }
@@ -709,7 +710,7 @@ MetricManager::forceEventLogging()
 }
 
 void
-MetricManager::reset(time_t currentTime)
+MetricManager::reset(system_time currentTime)
 {
     time_point preTime = _timer->getTimeInMilliSecs();
     // Resetting implies visiting metrics, which needs to grab metric lock
@@ -733,21 +734,21 @@ MetricManager::run()
     // we constantly add next time to do something from the last timer.
     // For that to work, we need to initialize timers on first iteration
     // to set them to current time.
-    time_t currentTime = count_s(_timer->getTime().time_since_epoch());
+    system_time currentTime = _timer->getTime();
     for (auto & snapshot : _snapshots) {
         snapshot->setFromTime(currentTime);
     }
     for (auto hook : _periodicUpdateHooks) {
-        hook->_nextCall = currentTime;
+        hook->_nextCall = count_s(currentTime.time_since_epoch());
     }
     // Ensure correct time for first snapshot
     _snapshots[0]->getSnapshot().setToTime(currentTime);
     while (!stop_requested()) {
-        time_point now = _timer->getTime();
-        currentTime = count_s(now.time_since_epoch());
-        time_t next = tick(sync, currentTime);
-        if (currentTime < next) {
-            vespalib::duration wait_time = from_s(next - currentTime);
+        currentTime = _timer->getTime();
+        time_t currentTimeS = count_s(currentTime.time_since_epoch());
+        time_t next = tick(sync, currentTimeS);
+        if (currentTimeS < next) {
+            vespalib::duration wait_time = from_s(next - currentTimeS);
             _cond.wait_for(sync, wait_time);
             _sleepTimes.addValue(count_ms(wait_time));
         } else {
@@ -772,7 +773,7 @@ MetricManager::tick(const MetricLockGuard & guard, time_t currentTime)
     checkMetricsAltered(guard);
 
         // Set next work time to the time we want to take next snapshot.
-    time_t nextWorkTime = _snapshots[0]->getToTime() + _snapshots[0]->getPeriod();
+    time_t nextWorkTime = count_s(_snapshots[0]->getToTime().time_since_epoch()) + _snapshots[0]->getPeriod();
     time_t nextUpdateHookTime;
     if (nextWorkTime <= currentTime) {
         // If taking a new snapshot or logging, force calls to all
@@ -787,41 +788,40 @@ MetricManager::tick(const MetricLockGuard & guard, time_t currentTime)
         nextUpdateHookTime = updatePeriodicMetrics(guard, currentTime, false);
     }
         // Do snapshotting if it is time
-    if (nextWorkTime <= currentTime) takeSnapshots(guard, nextWorkTime);
+    if (nextWorkTime <= currentTime) takeSnapshots(guard, system_time(from_s(nextWorkTime)));
 
     _lastProcessedTime.store(nextWorkTime <= currentTime ? nextWorkTime : currentTime, std::memory_order_relaxed);
     LOG(spam, "Worker thread done with processing for time %" PRIu64 ".",
         static_cast<uint64_t>(_lastProcessedTime.load(std::memory_order_relaxed)));
-    time_t next = _snapshots[0]->getPeriod() + _snapshots[0]->getToTime();
+    time_t next = count_s(_snapshots[0]->getToTime().time_since_epoch()) + _snapshots[0]->getPeriod();
     next = std::min(next, nextUpdateHookTime);
     return next;
 }
 
 void
-MetricManager::takeSnapshots(const MetricLockGuard & guard, time_t timeToProcess)
+MetricManager::takeSnapshots(const MetricLockGuard & guard, system_time timeToProcess)
 {
     assertMetricLockLocked(guard);
     // If not time to do dump data from active snapshot yet, nothing to do
     if (!_snapshots[0]->timeForAnotherSnapshot(timeToProcess)) {
-         LOG(spam, "Not time to process snapshot %s at time %" PRIu64 ". Current "
-                   "first period (%u) snapshot goes from %" PRIu64 " to %" PRIu64,
-             _snapshots[0]->getName().c_str(), static_cast<uint64_t>(timeToProcess),
-             _snapshots[0]->getPeriod(), static_cast<uint64_t>(_snapshots[0]->getFromTime()),
-             static_cast<uint64_t>(_snapshots[0]->getToTime()));
+         LOG(spam, "Not time to process snapshot %s at time %s. Current "
+                   "first period (%u) snapshot goes from %s to %s",
+             _snapshots[0]->getName().c_str(), to_string(timeToProcess).c_str(),
+             _snapshots[0]->getPeriod(), to_string(_snapshots[0]->getFromTime()).c_str(),
+             to_string(_snapshots[0]->getToTime()).c_str());
         return;
     }
     time_point preTime = _timer->getTimeInMilliSecs();
-    LOG(debug, "Updating %s snapshot and total metrics at time %" PRIu64 ".",
-        _snapshots[0]->getName().c_str(), static_cast<uint64_t>(timeToProcess));
+    LOG(debug, "Updating %s snapshot and total metrics at time %s.",
+        _snapshots[0]->getName().c_str(), to_string(timeToProcess).c_str());
     MetricSnapshot& firstTarget(_snapshots[0]->getNextTarget());
     firstTarget.reset(_activeMetrics.getFromTime());
     _activeMetrics.addToSnapshot(firstTarget, false, timeToProcess);
     _activeMetrics.addToSnapshot(*_totalMetrics, false, timeToProcess);
     _activeMetrics.reset(timeToProcess);
-    LOG(debug, "After snapshotting, active metrics goes from %" PRIu64 " to %" PRIu64", "
-               "and 5 minute metrics goes from %" PRIu64 " to %" PRIu64".",
-        static_cast<uint64_t>(_activeMetrics.getFromTime()), static_cast<uint64_t>(_activeMetrics.getToTime()),
-        static_cast<uint64_t>(firstTarget.getFromTime()), static_cast<uint64_t>(firstTarget.getToTime()));
+    LOG(debug, "After snapshotting, active metrics goes from %s to %s, and 5 minute metrics goes from %s to %s.",
+        to_string(_activeMetrics.getFromTime()).c_str(), to_string(_activeMetrics.getToTime()).c_str(),
+        to_string(firstTarget.getFromTime()).c_str(), to_string(firstTarget.getToTime()).c_str());
 
         // Update later snapshots if it is time for it
     for (uint32_t i=1; i<_snapshots.size(); ++i) {
@@ -831,15 +831,15 @@ MetricManager::takeSnapshots(const MetricLockGuard & guard, time_t timeToProcess
         _snapshots[i-1]->getSnapshot().addToSnapshot(target, false, timeToProcess);
         target.setToTime(timeToProcess);
         if (!_snapshots[i]->haveCompletedNewPeriod(timeToProcess)) {
-            LOG(debug, "Not time to roll snapshot %s yet. %u of %u snapshot taken at time %" PRIu64 ", and period of %u "
-                       "is not up yet as we're currently processing for time %" PRIu64 ".",
+            LOG(debug, "Not time to roll snapshot %s yet. %u of %u snapshot taken at time %s, and period of %u "
+                       "is not up yet as we're currently processing for time %s.",
                 _snapshots[i]->getName().c_str(), _snapshots[i]->getBuilderCount(), _snapshots[i]->getCount(),
-                static_cast<uint64_t>(_snapshots[i]->getBuilderCount() * _snapshots[i]->getPeriod() + _snapshots[i]->getFromTime()),
-                _snapshots[i]->getPeriod(), static_cast<uint64_t>(timeToProcess));
+                to_string(_snapshots[i]->getBuilderCount() * from_s(_snapshots[i]->getPeriod()) + _snapshots[i]->getFromTime()).c_str(),
+                _snapshots[i]->getPeriod(), to_string(timeToProcess).c_str());
             break;
         } else {
-            LOG(debug, "Rolled snapshot %s at time %" PRIu64 ".",
-                _snapshots[i]->getName().c_str(), static_cast<uint64_t>(timeToProcess));
+            LOG(debug, "Rolled snapshot %s at time %s.",
+                _snapshots[i]->getName().c_str(), to_string(timeToProcess).c_str());
         }
     }
     time_point postTime = _timer->getTimeInMilliSecs();
diff --git a/metrics/src/vespa/metrics/metricmanager.h b/metrics/src/vespa/metrics/metricmanager.h
index c3ce37b451f..e793ef80b7f 100644
--- a/metrics/src/vespa/metrics/metricmanager.h
+++ b/metrics/src/vespa/metrics/metricmanager.h
@@ -191,7 +191,7 @@ public:
      * Reset all metrics including all snapshots.
      * This function can not be called from an update hook callback.
      */
-    void reset(time_t currentTime);
+    void reset(system_time currentTime);
 
     /**
      * Read configuration. Before reading config, all metrics should be set
@@ -267,7 +267,7 @@ public:
     bool isInitialized() const;
 
 private:
-    void takeSnapshots(const MetricLockGuard &, time_t timeToProcess);
+    void takeSnapshots(const MetricLockGuard &, system_time timeToProcess);
 
     friend struct MetricManagerTest;
     friend struct SnapshotTest;
diff --git a/metrics/src/vespa/metrics/metricsnapshot.cpp b/metrics/src/vespa/metrics/metricsnapshot.cpp
index 1580f340f0e..d8c87ce52d9 100644
--- a/metrics/src/vespa/metrics/metricsnapshot.cpp
+++ b/metrics/src/vespa/metrics/metricsnapshot.cpp
@@ -6,13 +6,18 @@
 #include <vespa/log/log.h>
 LOG_SETUP(".metrics.snapshot");
 
+using vespalib::to_string;
+
+
 namespace metrics {
 
+static constexpr system_time system_time_epoch = system_time();
+
 MetricSnapshot::MetricSnapshot(const Metric::String& name)
     : _name(name),
       _period(0),
-      _fromTime(0),
-      _toTime(0),
+      _fromTime(system_time_epoch),
+      _toTime(system_time_epoch),
       _snapshot(new MetricSet("top", {}, "", nullptr)),
       _metrics()
 {
@@ -21,8 +26,8 @@ MetricSnapshot::MetricSnapshot(const Metric::String& name)
 MetricSnapshot::MetricSnapshot(const Metric::String& name, uint32_t period, const MetricSet& source, bool copyUnset)
     : _name(name),
       _period(period),
-      _fromTime(0),
-      _toTime(0),
+      _fromTime(system_time_epoch),
+      _toTime(system_time_epoch),
       _snapshot(),
       _metrics()
 {
@@ -35,10 +40,14 @@ MetricSnapshot::MetricSnapshot(const Metric::String& name, uint32_t period, cons
 MetricSnapshot::~MetricSnapshot() = default;
 
 void
-MetricSnapshot::reset(time_t currentTime)
+MetricSnapshot::reset() {
+    reset(system_time_epoch);
+}
+void
+MetricSnapshot::reset(system_time currentTime)
 {
     _fromTime = currentTime;
-    _toTime = 0;
+    _toTime = system_time_epoch;
     _snapshot->reset();
 }
 
@@ -61,22 +70,19 @@ MetricSnapshot::addMemoryUsage(MemoryConsumption& mc) const
 {
     ++mc._snapshotCount;
     mc._snapshotName += mc.getStringMemoryUsage(_name, mc._snapshotNameUnique);
-    mc._snapshotMeta += sizeof(MetricSnapshot)
-                      + _metrics.capacity() * sizeof(Metric::SP);
+    mc._snapshotMeta += sizeof(MetricSnapshot) + _metrics.capacity() * sizeof(Metric::SP);
     _snapshot->addMemoryUsage(mc);
 }
 
-MetricSnapshotSet::MetricSnapshotSet(
-        const Metric::String& name, uint32_t period,
-        uint32_t count, const MetricSet& source, bool snapshotUnsetMetrics)
+MetricSnapshotSet::MetricSnapshotSet(const Metric::String& name, uint32_t period, uint32_t count,
+                                     const MetricSet& source, bool snapshotUnsetMetrics)
     : _count(count),
       _builderCount(0),
-      _current(new MetricSnapshot(name, period, source, snapshotUnsetMetrics)),
-      _building(count == 1 ? 0 : new MetricSnapshot(
-                  name, period, source, snapshotUnsetMetrics))
+      _current(std::make_unique<MetricSnapshot>(name, period, source, snapshotUnsetMetrics)),
+      _building(count == 1 ? nullptr : new MetricSnapshot(name, period, source, snapshotUnsetMetrics))
 {
-    _current->reset(0);
-    if (_building.get()) _building->reset(0);
+    _current->reset();
+    if (_building.get()) _building->reset();
 }
 
 MetricSnapshot&
@@ -87,16 +93,16 @@ MetricSnapshotSet::getNextTarget()
 }
 
 bool
-MetricSnapshotSet::haveCompletedNewPeriod(time_t newFromTime)
+MetricSnapshotSet::haveCompletedNewPeriod(system_time newFromTime)
 {
     if (_count == 1) {
         _current->setToTime(newFromTime);
         return true;
     }
     _building->setToTime(newFromTime);
-        // If not time to roll yet, just return
+    // If not time to roll yet, just return
     if (++_builderCount < _count) return false;
-        // Building buffer done. Use that as current and reset current.
+    // Building buffer done. Use that as current and reset current.
     MetricSnapshot::UP tmp(std::move(_current));
     _current = std::move(_building);
     _building = std::move(tmp);
@@ -106,16 +112,15 @@ MetricSnapshotSet::haveCompletedNewPeriod(time_t newFromTime)
 }
 
 bool
-MetricSnapshotSet::timeForAnotherSnapshot(time_t currentTime) {
-    time_t lastTime = getToTime();
-    if (currentTime >= lastTime + getPeriod()) {
-        if (currentTime >= lastTime + 2 * getPeriod()) {
-            LOG(warning, "Metric snapshot set %s was asked if it was time for "
-                         "another snapshot, a whole period beyond when it "
-                         "should have been done (Last update was at time %lu"
-                         ", current time is %lu and period is %u). "
-                         "Clearing data and updating time to current time.",
-                getName().c_str(), lastTime, currentTime, getPeriod());
+MetricSnapshotSet::timeForAnotherSnapshot(system_time currentTime) {
+    system_time lastTime = getToTime();
+    vespalib::duration period = vespalib::from_s(getPeriod());
+    if (currentTime >= lastTime + period) {
+        if (currentTime >= lastTime + 2 * period) {
+            LOG(warning, "Metric snapshot set %s was asked if it was time for another snapshot, a whole period beyond "
+                         "when it should have been done (Last update was at time %s, current time is %s and period "
+                         "is %u). Clearing data and updating time to current time.",
+                getName().c_str(), to_string(lastTime).c_str(), to_string(currentTime).c_str(), getPeriod());
             reset(currentTime);
         }
         return true;
@@ -124,7 +129,7 @@ MetricSnapshotSet::timeForAnotherSnapshot(time_t currentTime) {
 }
 
 void
-MetricSnapshotSet::reset(time_t currentTime) {
+MetricSnapshotSet::reset(system_time currentTime) {
     if (_count != 1) _building->reset(currentTime);
     _current->reset(currentTime);
     _builderCount = 0;
@@ -147,7 +152,7 @@ MetricSnapshotSet::addMemoryUsage(MemoryConsumption& mc) const
 }
 
 void
-MetricSnapshotSet::setFromTime(time_t fromTime)
+MetricSnapshotSet::setFromTime(system_time fromTime)
 {
     if (_count != 1) _building->setFromTime(fromTime);
     _current->setFromTime(fromTime);
diff --git a/metrics/src/vespa/metrics/metricsnapshot.h b/metrics/src/vespa/metrics/metricsnapshot.h
index cc6ec4cbb2e..16b46760957 100644
--- a/metrics/src/vespa/metrics/metricsnapshot.h
+++ b/metrics/src/vespa/metrics/metricsnapshot.h
@@ -15,6 +15,8 @@
 
 namespace metrics {
 
+using system_time = vespalib::system_time;
+
 class MetricManager;
 
 class MetricSnapshot
@@ -23,9 +25,9 @@ class MetricSnapshot
         // Period length of this snapshot
     uint32_t _period;
         // Time this snapshot was last updated.
-    time_t _fromTime;
+    system_time _fromTime;
         // If set to 0, use _fromTime + _period.
-    time_t _toTime;
+    system_time _toTime;
         // Keeps the metrics set view of the snapshot
     std::unique_ptr<MetricSet> _snapshot;
         // Snapshots must own their own metrics
@@ -42,27 +44,26 @@ public:
                    const MetricSet& source, bool copyUnset);
     virtual ~MetricSnapshot();
 
-    void addToSnapshot(MetricSnapshot& other, bool reset_, time_t currentTime) {
+    void addToSnapshot(MetricSnapshot& other, bool reset_, system_time currentTime) {
         _snapshot->addToSnapshot(other.getMetrics(), other._metrics);
         if (reset_) reset(currentTime);
         other._toTime = currentTime;
     }
-    void addToSnapshot(MetricSnapshot& other, time_t currentTime) const {
+    void addToSnapshot(MetricSnapshot& other, system_time currentTime) const {
         _snapshot->addToSnapshot(other.getMetrics(), other._metrics);
         other._toTime = currentTime;
     }
-    void setFromTime(time_t fromTime) { _fromTime = fromTime; }
-    void setToTime(time_t toTime) { _toTime = toTime; }
+    void setFromTime(system_time fromTime) { _fromTime = fromTime; }
+    void setToTime(system_time toTime) { _toTime = toTime; }
 
     const Metric::String& getName() const { return _name; }
     uint32_t getPeriod() const { return _period; }
-    time_t getFromTime() const { return _fromTime; }
-    time_t getToTime() const { return _toTime; }
-    time_t getLength() const
-        { return (_toTime != 0 ? _toTime - _fromTime : _fromTime + _period); }
+    system_time getFromTime() const { return _fromTime; }
+    system_time getToTime() const { return _toTime; }
     const MetricSet& getMetrics() const { return *_snapshot; }
     MetricSet& getMetrics() { return *_snapshot; }
-    void reset(time_t currentTime);
+    void reset(system_time currentTime);
+    void reset();
     /**
      * Recreate snapshot by cloning given metric set and then add the data
      * from the old one. New metrics have been added.
@@ -82,32 +83,32 @@ class MetricSnapshotSet {
 public:
     using SP = std::shared_ptr<MetricSnapshotSet>;
 
-    MetricSnapshotSet(const Metric::String& name, uint32_t period,
-                      uint32_t count, const MetricSet& source,
-                      bool snapshotUnsetMetrics);
+    MetricSnapshotSet(const Metric::String& name, uint32_t period, uint32_t count,
+                      const MetricSet& source, bool snapshotUnsetMetrics);
 
     const Metric::String& getName() const { return _current->getName(); }
     uint32_t getPeriod() const { return _current->getPeriod(); }
-    time_t getFromTime() const { return _current->getFromTime(); }
-    time_t getToTime() const { return _current->getToTime(); }
+    system_time getFromTime() const { return _current->getFromTime(); }
+    system_time getToTime() const { return _current->getToTime(); }
     uint32_t getCount() const { return _count; }
     uint32_t getBuilderCount() const { return _builderCount; }
-    bool hasTemporarySnapshot() const { return (_building.get() != 0); }
-    MetricSnapshot& getSnapshot(bool temporary = false)
-        { return *((temporary && _count > 1) ? _building : _current); }
-    const MetricSnapshot& getSnapshot(bool temporary = false) const
-        { return *((temporary && _count > 1) ? _building : _current); }
+    MetricSnapshot& getSnapshot(bool temporary = false) {
+        return *((temporary && _count > 1) ? _building : _current);
+    }
+    const MetricSnapshot& getSnapshot(bool temporary = false) const {
+        return *((temporary && _count > 1) ? _building : _current);
+    }
     MetricSnapshot& getNextTarget();
-    bool timeForAnotherSnapshot(time_t currentTime);
-    bool haveCompletedNewPeriod(time_t newFromTime);
-    void reset(time_t currentTime);
+    bool timeForAnotherSnapshot(system_time currentTime);
+    bool haveCompletedNewPeriod(system_time newFromTime);
+    void reset(system_time currentTime);
     /**
      * Recreate snapshot by cloning given metric set and then add the data
      * from the old one. New metrics have been added.
      */
     void recreateSnapshot(const MetricSet& metrics, bool copyUnset);
     void addMemoryUsage(MemoryConsumption&) const;
-    void setFromTime(time_t fromTime);
+    void setFromTime(system_time fromTime);
 };
 
 } // metrics
diff --git a/metrics/src/vespa/metrics/state_api_adapter.cpp b/metrics/src/vespa/metrics/state_api_adapter.cpp
index 61a1ce7c2a9..793267bfbf4 100644
--- a/metrics/src/vespa/metrics/state_api_adapter.cpp
+++ b/metrics/src/vespa/metrics/state_api_adapter.cpp
@@ -29,8 +29,8 @@ StateApiAdapter::getTotalMetrics(const vespalib::string &consumer)
     _manager.updateMetrics(true);
     metrics::MetricLockGuard guard(_manager.getMetricLock());
     _manager.checkMetricsAltered(guard);
-    time_t currentTime = vespalib::count_s(vespalib::steady_clock::now().time_since_epoch());
-   auto generated = std::make_unique<metrics::MetricSnapshot>(
+    system_time currentTime = vespalib::system_clock::now();
+    auto generated = std::make_unique<metrics::MetricSnapshot>(
            "Total metrics from start until current time", 0,
            _manager.getTotalMetricSnapshot(guard).getMetrics(),
            true);
diff --git a/metrics/src/vespa/metrics/textwriter.cpp b/metrics/src/vespa/metrics/textwriter.cpp
index 94a7b7df73b..cc9a68f2b3d 100644
--- a/metrics/src/vespa/metrics/textwriter.cpp
+++ b/metrics/src/vespa/metrics/textwriter.cpp
@@ -7,6 +7,8 @@
 #include "valuemetric.h"
 #include <sstream>
 
+using vespalib::to_string;
+
 namespace metrics {
 
 TextWriter::TextWriter(std::ostream& out, uint32_t period,
@@ -19,13 +21,13 @@ TextWriter::TextWriter(std::ostream& out, uint32_t period,
     }
 }
 
-TextWriter::~TextWriter() { }
+TextWriter::~TextWriter() = default;
 
 bool
 TextWriter::visitSnapshot(const MetricSnapshot& snapshot)
 {
     _out << "snapshot \"" << snapshot.getName() << "\" from "
-         << snapshot.getFromTime() << " to " << snapshot.getToTime()
+         << to_string(snapshot.getFromTime()) << " to " << to_string(snapshot.getToTime())
          << " period " << snapshot.getPeriod();
     return true;
 }
diff --git a/storage/src/vespa/storage/common/statusmetricconsumer.cpp b/storage/src/vespa/storage/common/statusmetricconsumer.cpp
index c6f73540605..5998a2fe9a9 100644
--- a/storage/src/vespa/storage/common/statusmetricconsumer.cpp
+++ b/storage/src/vespa/storage/common/statusmetricconsumer.cpp
@@ -61,7 +61,7 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
     } else {
         LOG(debug, "Not calling update hooks as dontcallupdatehooks option has been given");
     }
-    int64_t currentTimeS(vespalib::count_s(_component.getClock().getMonotonicTime().time_since_epoch()));
+    vespalib::system_time currentTime = _component.getClock().getSystemTime();
     bool json = (path.getAttribute("format") == "json");
 
     int verbosity(path.get("verbosity", 0));
@@ -72,7 +72,7 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
 
     if (path.hasAttribute("task") && path.getAttribute("task") == "reset") {
         std::lock_guard guard(_lock);
-        _manager.reset(currentTimeS);
+        _manager.reset(currentTime);
     }
 
     if (path.hasAttribute("interval")) {
@@ -83,7 +83,7 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
         const metrics::MetricSnapshot* snapshot;
         if (interval == -2) {
             snapshot = &_manager.getActiveMetrics(metricLock);
-            _manager.getActiveMetrics(metricLock).setToTime(currentTimeS);
+            _manager.getActiveMetrics(metricLock).setToTime(currentTime);
         } else if (interval == -1) {
             // "Prime" the metric structure by first fetching the set of active
             // metrics (complete with structure) and resetting these. This
@@ -94,9 +94,9 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
                     "Total metrics from start until current time", 0,
                     _manager.getActiveMetrics(metricLock).getMetrics(),
                     copyUnset);
-            generated->reset(0);
-            _manager.getTotalMetricSnapshot(metricLock).addToSnapshot(*generated, currentTimeS);
-            _manager.getActiveMetrics(metricLock).addToSnapshot(*generated, currentTimeS);
+            generated->reset();
+            _manager.getTotalMetricSnapshot(metricLock).addToSnapshot(*generated, currentTime);
+            _manager.getActiveMetrics(metricLock).addToSnapshot(*generated, currentTime);
             generated->setFromTime(_manager.getTotalMetricSnapshot(metricLock).getFromTime());
             snapshot = generated.get();
         } else if (interval == 0) {
@@ -104,8 +104,8 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
                 generated = std::make_unique<metrics::MetricSnapshot>(
                         _manager.getTotalMetricSnapshot(metricLock).getName(), 0,
                         _manager.getActiveMetrics(metricLock).getMetrics(), true);
-                generated->reset(0);
-                _manager.getTotalMetricSnapshot(metricLock).addToSnapshot(*generated, currentTimeS);
+                generated->reset();
+                _manager.getTotalMetricSnapshot(metricLock).addToSnapshot(*generated, currentTime);
                 snapshot = generated.get();
             } else {
                 snapshot = &_manager.getTotalMetricSnapshot(metricLock);
@@ -115,9 +115,9 @@ StatusMetricConsumer::reportStatus(std::ostream& out,
                 generated = std::make_unique<metrics::MetricSnapshot>(
                         _manager.getMetricSnapshot(metricLock, interval).getName(), 0,
                         _manager.getActiveMetrics(metricLock).getMetrics(), true);
-                generated->reset(0);
+                generated->reset();
                 _manager.getMetricSnapshot(metricLock, interval, temporarySnap)
-                        .addToSnapshot(*generated, currentTimeS);
+                        .addToSnapshot(*generated, currentTime);
                 snapshot = generated.get();
             } else {
                 snapshot = &_manager.getMetricSnapshot(metricLock, interval, temporarySnap);
diff --git a/storage/src/vespa/storage/storageserver/statereporter.cpp b/storage/src/vespa/storage/storageserver/statereporter.cpp
index 205a2d710a6..79746f2cd63 100644
--- a/storage/src/vespa/storage/storageserver/statereporter.cpp
+++ b/storage/src/vespa/storage/storageserver/statereporter.cpp
@@ -81,9 +81,8 @@ StateReporter::getMetrics(const vespalib::string &consumer)
             _manager.getMetricSnapshot(guard, interval).getName(), interval,
             _manager.getActiveMetrics(guard).getMetrics(), true);
 
-    snapshot.reset(0);
-    _manager.getMetricSnapshot(guard, interval).addToSnapshot(
-            snapshot, vespalib::count_s(_component.getClock().getSystemTime().time_since_epoch()));
+    snapshot.reset();
+    _manager.getMetricSnapshot(guard, interval).addToSnapshot(snapshot, _component.getClock().getSystemTime());
 
     vespalib::asciistream json;
     vespalib::JsonStream stream(json);