diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index f0723e8..fa6ef25 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4135,6 +4135,10 @@
         getHwComposer().setPowerMode(type, mode);
     }
 
+    if (display->isPrimary()) {
+        mTimeStats.setPowerMode(mode);
+    }
+
     ALOGD("Finished setting power mode %d on display %d", mode, displayId);
 }
 
diff --git a/services/surfaceflinger/TimeStats/TimeStats.cpp b/services/surfaceflinger/TimeStats/TimeStats.cpp
index 6fb70f8..c14d93b 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.cpp
+++ b/services/surfaceflinger/TimeStats/TimeStats.cpp
@@ -24,6 +24,7 @@
 #include <log/log.h>
 
 #include <utils/String8.h>
+#include <utils/Timers.h>
 #include <utils/Trace.h>
 
 #include <algorithm>
@@ -445,6 +446,39 @@
     layerRecord.droppedFrames++;
 }
 
+void TimeStats::flushPowerTimeLocked() {
+    nsecs_t curTime = systemTime();
+    // elapsedTime is in milliseconds.
+    int64_t elapsedTime = (curTime - mPowerTime.prevTime) / 1000000;
+
+    switch (mPowerTime.powerMode) {
+        case HWC_POWER_MODE_NORMAL:
+            mTimeStats.displayOnTime += elapsedTime;
+            break;
+        case HWC_POWER_MODE_OFF:
+        case HWC_POWER_MODE_DOZE:
+        case HWC_POWER_MODE_DOZE_SUSPEND:
+        default:
+            break;
+    }
+
+    mPowerTime.prevTime = curTime;
+}
+
+void TimeStats::setPowerMode(int32_t powerMode) {
+    if (!mEnabled.load()) {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mPowerTime.powerMode = powerMode;
+        return;
+    }
+
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (powerMode == mPowerTime.powerMode) return;
+
+    flushPowerTimeLocked();
+    mPowerTime.powerMode = powerMode;
+}
+
 void TimeStats::enable() {
     if (mEnabled.load()) return;
 
@@ -454,6 +488,7 @@
     ALOGD("Enabled");
     mEnabled.store(true);
     mTimeStats.statsStart = static_cast<int64_t>(std::time(0));
+    mPowerTime.prevTime = systemTime();
 }
 
 void TimeStats::disable() {
@@ -478,6 +513,8 @@
     mTimeStats.totalFrames = 0;
     mTimeStats.missedFrames = 0;
     mTimeStats.clientCompositionFrames = 0;
+    mTimeStats.displayOnTime = 0;
+    mPowerTime.prevTime = systemTime();
 }
 
 bool TimeStats::isEnabled() {
@@ -494,6 +531,8 @@
 
     mTimeStats.statsEnd = static_cast<int64_t>(std::time(0));
 
+    flushPowerTimeLocked();
+
     if (asProto) {
         ALOGD("Dumping TimeStats as proto");
         SFTimeStatsGlobalProto timeStatsProto = mTimeStats.toProto(maxLayers);
diff --git a/services/surfaceflinger/TimeStats/TimeStats.h b/services/surfaceflinger/TimeStats/TimeStats.h
index 6ae6b15..87e21a7 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.h
+++ b/services/surfaceflinger/TimeStats/TimeStats.h
@@ -19,6 +19,8 @@
 #include <timestatsproto/TimeStatsHelper.h>
 #include <timestatsproto/TimeStatsProtoHeader.h>
 
+#include <hardware/hwcomposer_defs.h>
+
 #include <ui/FenceTime.h>
 
 #include <utils/String16.h>
@@ -66,6 +68,11 @@
         std::deque<TimeRecord> timeRecords;
     };
 
+    struct PowerTime {
+        int32_t powerMode = HWC_POWER_MODE_OFF;
+        nsecs_t prevTime = 0;
+    };
+
 public:
     static TimeStats& getInstance();
     void parseArgs(bool asProto, const Vector<String16>& args, size_t& index, String8& result);
@@ -91,11 +98,14 @@
     // If SF skips or rejects a buffer, remove the corresponding TimeRecord.
     void removeTimeRecord(const std::string& layerName, uint64_t frameNumber);
 
+    void setPowerMode(int32_t powerMode);
+
 private:
     TimeStats() = default;
 
     bool recordReadyLocked(const std::string& layerName, TimeRecord* timeRecord);
     void flushAvailableRecordsToStatsLocked(const std::string& layerName);
+    void flushPowerTimeLocked();
 
     void enable();
     void disable();
@@ -107,6 +117,7 @@
     std::mutex mMutex;
     TimeStatsHelper::TimeStatsGlobal mTimeStats;
     std::unordered_map<std::string, LayerRecord> mTimeStatsTracker;
+    PowerTime mPowerTime;
 };
 
 } // namespace android
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp b/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
index b7b2778..ec41a62 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
+++ b/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
@@ -49,7 +49,7 @@
 float TimeStatsHelper::Histogram::averageTime() const {
     int64_t ret = 0;
     int64_t count = 0;
-    for (auto& ele : hist) {
+    for (const auto& ele : hist) {
         count += ele.second;
         ret += ele.first * ele.second;
     }
@@ -73,13 +73,13 @@
     StringAppendF(&result, "packageName = %s\n", packageName.c_str());
     StringAppendF(&result, "totalFrames = %d\n", totalFrames);
     StringAppendF(&result, "droppedFrames = %d\n", droppedFrames);
-    auto iter = deltas.find("present2present");
+    const auto iter = deltas.find("present2present");
     if (iter != deltas.end()) {
         StringAppendF(&result, "averageFPS = %.3f\n", 1000.0 / iter->second.averageTime());
     }
-    for (auto& ele : deltas) {
+    for (const auto& ele : deltas) {
         StringAppendF(&result, "%s histogram is as below:\n", ele.first.c_str());
-        StringAppendF(&result, "%s", ele.second.toString().c_str());
+        result.append(ele.second.toString());
     }
 
     return result;
@@ -92,9 +92,10 @@
     StringAppendF(&result, "totalFrames = %d\n", totalFrames);
     StringAppendF(&result, "missedFrames = %d\n", missedFrames);
     StringAppendF(&result, "clientCompositionFrames = %d\n", clientCompositionFrames);
+    StringAppendF(&result, "displayOnTime = %lld ms\n", static_cast<long long int>(displayOnTime));
     const auto dumpStats = generateDumpStats(maxLayers);
-    for (auto& ele : dumpStats) {
-        StringAppendF(&result, "%s", ele->toString().c_str());
+    for (const auto& ele : dumpStats) {
+        result.append(ele->toString());
     }
 
     return result;
@@ -106,10 +107,10 @@
     layerProto.set_package_name(packageName);
     layerProto.set_total_frames(totalFrames);
     layerProto.set_dropped_frames(droppedFrames);
-    for (auto& ele : deltas) {
+    for (const auto& ele : deltas) {
         SFTimeStatsDeltaProto* deltaProto = layerProto.add_deltas();
         deltaProto->set_delta_name(ele.first);
-        for (auto& histEle : ele.second.hist) {
+        for (const auto& histEle : ele.second.hist) {
             SFTimeStatsHistogramBucketProto* histProto = deltaProto->add_histograms();
             histProto->set_time_millis(histEle.first);
             histProto->set_frame_count(histEle.second);
@@ -126,8 +127,9 @@
     globalProto.set_total_frames(totalFrames);
     globalProto.set_missed_frames(missedFrames);
     globalProto.set_client_composition_frames(clientCompositionFrames);
+    globalProto.set_display_on_time(displayOnTime);
     const auto dumpStats = generateDumpStats(maxLayers);
-    for (auto& ele : dumpStats) {
+    for (const auto& ele : dumpStats) {
         SFTimeStatsLayerProto* layerProto = globalProto.add_stats();
         layerProto->CopyFrom(ele->toProto());
     }
@@ -137,7 +139,7 @@
 std::vector<TimeStatsHelper::TimeStatsLayer const*>
 TimeStatsHelper::TimeStatsGlobal::generateDumpStats(std::optional<uint32_t> maxLayers) const {
     std::vector<TimeStatsLayer const*> dumpStats;
-    for (auto& ele : stats) {
+    for (const auto& ele : stats) {
         dumpStats.push_back(&ele.second);
     }
 
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
index 99c891b..939e137 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
+++ b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
@@ -57,6 +57,7 @@
         int32_t totalFrames = 0;
         int32_t missedFrames = 0;
         int32_t clientCompositionFrames = 0;
+        int64_t displayOnTime = 0;
         std::unordered_map<std::string, TimeStatsLayer> stats;
 
         std::string toString(std::optional<uint32_t> maxLayers) const;
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto b/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
index b8f38c2..f584496 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
+++ b/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
@@ -20,13 +20,12 @@
 
 option optimize_for = LITE_RUNTIME;
 
-// //depot/google3/java/com/google/android/apps/graphics/stats/proto/
+// //depot/google3/wireless/android/graphics/surfaceflingerstats/proto/
 // timestats.proto is based on this proto. Please only make valid protobuf
-// changes to these messages, and keep the other file in sync per Android
-// release. Please also do not include "option optimize_for = LITE_RUNTIME;" at
-// google3 side.
+// changes to these messages, and keep google3 side proto messages in sync if
+// the end to end pipeline needs to be updated.
 
-// Next tag: 7
+// Next tag: 8
 message SFTimeStatsGlobalProto {
   // The stats start time in UTC as seconds since January 1, 1970
   optional int64 stats_start = 1;
@@ -38,6 +37,8 @@
   optional int32 missed_frames = 4;
   // Total frames fallback to client composition.
   optional int32 client_composition_frames = 5;
+  // Primary display on time in milliseconds.
+  optional int64 display_on_time = 7;
   // Stats per layer. Apps could have multiple layers.
   repeated SFTimeStatsLayerProto stats = 6;
 }