diff --git a/cmds/statsd/src/StatsLogProcessor.cpp b/cmds/statsd/src/StatsLogProcessor.cpp
index a35570b..dac731d 100644
--- a/cmds/statsd/src/StatsLogProcessor.cpp
+++ b/cmds/statsd/src/StatsLogProcessor.cpp
@@ -87,7 +87,7 @@
 }
 
 void StatsLogProcessor::onAnomalyAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>> alarmSet) {
     std::lock_guard<std::mutex> lock(mMetricsMutex);
     for (const auto& itr : mMetricsManagers) {
@@ -95,7 +95,7 @@
     }
 }
 void StatsLogProcessor::onPeriodicAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>> alarmSet) {
 
     std::lock_guard<std::mutex> lock(mMetricsMutex);
diff --git a/cmds/statsd/src/StatsLogProcessor.h b/cmds/statsd/src/StatsLogProcessor.h
index a07a355..387a929 100644
--- a/cmds/statsd/src/StatsLogProcessor.h
+++ b/cmds/statsd/src/StatsLogProcessor.h
@@ -51,12 +51,12 @@
 
     /* Tells MetricsManager that the alarms in alarmSet have fired. Modifies anomaly alarmSet. */
     void onAnomalyAlarmFired(
-            const uint64_t timestampNs,
+            const uint64_t& timestampNs,
             unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>> alarmSet);
 
     /* Tells MetricsManager that the alarms in alarmSet have fired. Modifies periodic alarmSet. */
     void onPeriodicAlarmFired(
-            const uint64_t timestampNs,
+            const uint64_t& timestampNs,
             unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>> alarmSet);
 
     /* Flushes data to disk. Data on memory will be gone after written to disk. */
@@ -74,6 +74,10 @@
         return mAnomalyAlarmMonitor;
     }
 
+    inline sp<AlarmMonitor> getPeriodicAlarmMonitor() const {
+        return mPeriodicAlarmMonitor;
+    }
+
     mutable mutex mMetricsMutex;
 
     std::unordered_map<ConfigKey, sp<MetricsManager>> mMetricsManagers;
@@ -147,6 +151,7 @@
     FRIEND_TEST(AnomalyDetectionE2eTest, TestDurationMetric_SUM_single_bucket);
     FRIEND_TEST(AnomalyDetectionE2eTest, TestDurationMetric_SUM_multiple_buckets);
     FRIEND_TEST(AnomalyDetectionE2eTest, TestDurationMetric_SUM_long_refractory_period);
+    FRIEND_TEST(AlarmE2eTest, TestMultipleAlarms);
 };
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/StatsService.cpp b/cmds/statsd/src/StatsService.cpp
index b03b4b4..1921528 100644
--- a/cmds/statsd/src/StatsService.cpp
+++ b/cmds/statsd/src/StatsService.cpp
@@ -698,7 +698,7 @@
                 "Only system uid can call informAlarmForSubscriberTriggeringFired");
     }
 
-    uint64_t currentTimeSec = time(nullptr);
+    uint64_t currentTimeSec = getElapsedRealtimeSec();
     std::unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>> alarmSet =
             mPeriodicAlarmMonitor->popSoonerThan(static_cast<uint32_t>(currentTimeSec));
     if (alarmSet.size() > 0) {
diff --git a/cmds/statsd/src/anomaly/AlarmTracker.cpp b/cmds/statsd/src/anomaly/AlarmTracker.cpp
index eb28383..249cb59 100644
--- a/cmds/statsd/src/anomaly/AlarmTracker.cpp
+++ b/cmds/statsd/src/anomaly/AlarmTracker.cpp
@@ -39,12 +39,14 @@
     VLOG("AlarmTracker() called");
     mAlarmSec = (startMillis + mAlarmConfig.offset_millis()) / MS_PER_SEC;
     mInternalAlarm = new InternalAlarm{static_cast<uint32_t>(mAlarmSec)};
-    mAlarmMonitor->add(mInternalAlarm);
+    if (mAlarmMonitor != nullptr) {
+        mAlarmMonitor->add(mInternalAlarm);
+    }
 }
 
 AlarmTracker::~AlarmTracker() {
     VLOG("~AlarmTracker() called");
-    if (mInternalAlarm != nullptr) {
+    if (mInternalAlarm != nullptr && mAlarmMonitor != nullptr) {
         mAlarmMonitor->remove(mInternalAlarm);
     }
 }
@@ -61,7 +63,8 @@
 void AlarmTracker::informAlarmsFired(
         const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& firedAlarms) {
-    if (firedAlarms.empty() || firedAlarms.find(mInternalAlarm) == firedAlarms.end()) {
+    if (firedAlarms.empty() || mInternalAlarm == nullptr ||
+        firedAlarms.find(mInternalAlarm) == firedAlarms.end()) {
         return;
     }
     if (!mSubscriptions.empty()) {
@@ -69,9 +72,11 @@
                            mSubscriptions);
     }
     firedAlarms.erase(mInternalAlarm);
-    mAlarmSec = findNextAlarmSec(timestampNs / NS_PER_SEC);
+    mAlarmSec = findNextAlarmSec((timestampNs-1) / NS_PER_SEC + 1); // round up
     mInternalAlarm = new InternalAlarm{static_cast<uint32_t>(mAlarmSec)};
-    mAlarmMonitor->add(mInternalAlarm);
+    if (mAlarmMonitor != nullptr) {
+        mAlarmMonitor->add(mInternalAlarm);
+    }
 }
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/anomaly/AlarmTracker.h b/cmds/statsd/src/anomaly/AlarmTracker.h
index d59dacaa..13180a5 100644
--- a/cmds/statsd/src/anomaly/AlarmTracker.h
+++ b/cmds/statsd/src/anomaly/AlarmTracker.h
@@ -48,6 +48,11 @@
             unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& firedAlarms);
 
 protected:
+    // For test only. Returns the alarm timestamp in seconds. Otherwise returns 0.
+    inline uint32_t getAlarmTimestampSec() const {
+        return mInternalAlarm == nullptr ? 0 : mInternalAlarm->timestampSec;
+    }
+
     uint64_t findNextAlarmSec(uint64_t currentTimeMillis);
 
     // statsd_config.proto Alarm message that defines this tracker.
@@ -69,6 +74,7 @@
     sp<const InternalAlarm> mInternalAlarm;
 
     FRIEND_TEST(AlarmTrackerTest, TestTriggerTimestamp);
+    FRIEND_TEST(AlarmE2eTest, TestMultipleAlarms);
 };
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/metrics/MetricsManager.cpp b/cmds/statsd/src/metrics/MetricsManager.cpp
index c773d4f..80a860c 100644
--- a/cmds/statsd/src/metrics/MetricsManager.cpp
+++ b/cmds/statsd/src/metrics/MetricsManager.cpp
@@ -350,7 +350,7 @@
 }
 
 void MetricsManager::onAnomalyAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& alarmSet) {
     for (const auto& itr : mAllAnomalyTrackers) {
         itr->informAlarmsFired(timestampNs, alarmSet);
@@ -358,7 +358,7 @@
 }
 
 void MetricsManager::onPeriodicAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& alarmSet) {
     for (const auto& itr : mAllPeriodicAlarmTrackers) {
         itr->informAlarmsFired(timestampNs, alarmSet);
diff --git a/cmds/statsd/src/metrics/MetricsManager.h b/cmds/statsd/src/metrics/MetricsManager.h
index 05ce84d..da0cd4a 100644
--- a/cmds/statsd/src/metrics/MetricsManager.h
+++ b/cmds/statsd/src/metrics/MetricsManager.h
@@ -48,11 +48,11 @@
     void onLogEvent(const LogEvent& event);
 
     void onAnomalyAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& alarmSet);
 
     void onPeriodicAlarmFired(
-        const uint64_t timestampNs,
+        const uint64_t& timestampNs,
         unordered_set<sp<const InternalAlarm>, SpHash<InternalAlarm>>& alarmSet);
 
     void notifyAppUpgrade(const uint64_t& eventTimeNs, const string& apk, const int uid,
@@ -184,6 +184,7 @@
     FRIEND_TEST(AnomalyDetectionE2eTest, TestDurationMetric_SUM_multiple_buckets);
     FRIEND_TEST(AnomalyDetectionE2eTest, TestDurationMetric_SUM_long_refractory_period);
 
+    FRIEND_TEST(AlarmE2eTest, TestMultipleAlarms);
 };
 
 }  // namespace statsd