diff --git a/services/surfaceflinger/TimeStats/TimeStats.cpp b/services/surfaceflinger/TimeStats/TimeStats.cpp
index d7a2886..d77a324 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.cpp
+++ b/services/surfaceflinger/TimeStats/TimeStats.cpp
@@ -178,10 +178,17 @@
             if (!timeStats.stats.count(layerName)) {
                 timeStats.stats[layerName].layerName = layerName;
                 timeStats.stats[layerName].packageName = getPackageName(layerName);
-                timeStats.stats[layerName].statsStart = static_cast<int64_t>(std::time(0));
             }
             TimeStatsHelper::TimeStatsLayer& timeStatsLayer = timeStats.stats[layerName];
             timeStatsLayer.totalFrames++;
+            timeStatsLayer.droppedFrames += layerRecord.droppedFrames;
+            layerRecord.droppedFrames = 0;
+
+            const int32_t postToAcquireMs = msBetween(timeRecords[0].frameTime.postTime,
+                                                      timeRecords[0].frameTime.acquireTime);
+            ALOGV("[%s]-[%" PRIu64 "]-post2acquire[%d]", layerName.c_str(),
+                  timeRecords[0].frameTime.frameNumber, postToAcquireMs);
+            timeStatsLayer.deltas["post2acquire"].insert(postToAcquireMs);
 
             const int32_t postToPresentMs = msBetween(timeRecords[0].frameTime.postTime,
                                                       timeRecords[0].frameTime.presentTime);
@@ -212,8 +219,6 @@
             ALOGV("[%s]-[%" PRIu64 "]-present2present[%d]", layerName.c_str(),
                   timeRecords[0].frameTime.frameNumber, presentToPresentMs);
             timeStatsLayer.deltas["present2present"].insert(presentToPresentMs);
-
-            timeStats.stats[layerName].statsEnd = static_cast<int64_t>(std::time(0));
         }
         prevTimeRecord = timeRecords[0];
         timeRecords.pop_front();
@@ -403,6 +408,7 @@
     layerRecord.timeRecords.clear();
     layerRecord.prevTimeRecord.ready = false;
     layerRecord.waitData = -1;
+    layerRecord.droppedFrames = 0;
 }
 
 void TimeStats::removeTimeRecord(const std::string& layerName, uint64_t frameNumber) {
@@ -422,8 +428,9 @@
     if (removeAt == layerRecord.timeRecords.size()) return;
     layerRecord.timeRecords.erase(layerRecord.timeRecords.begin() + removeAt);
     if (layerRecord.waitData > static_cast<int32_t>(removeAt)) {
-        --layerRecord.waitData;
+        layerRecord.waitData--;
     }
+    layerRecord.droppedFrames++;
 }
 
 void TimeStats::enable() {
diff --git a/services/surfaceflinger/TimeStats/TimeStats.h b/services/surfaceflinger/TimeStats/TimeStats.h
index 0b1f82e..5ab3934 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.h
+++ b/services/surfaceflinger/TimeStats/TimeStats.h
@@ -61,6 +61,7 @@
         // specific frame are still not fully received. This is not waiting for
         // fences to signal, but rather waiting to receive those fences/timestamps.
         int32_t waitData = -1;
+        uint32_t droppedFrames = 0;
         TimeRecord prevTimeRecord;
         std::deque<TimeRecord> timeRecords;
     };
@@ -81,8 +82,11 @@
     void setPresentTime(const std::string& layerName, uint64_t frameNumber, nsecs_t presentTime);
     void setPresentFence(const std::string& layerName, uint64_t frameNumber,
                          const std::shared_ptr<FenceTime>& presentFence);
+    // On producer disconnect with BufferQueue.
     void onDisconnect(const std::string& layerName);
+    // When SF is cleaning up the queue, clear the LayerRecord as well.
     void clearLayerRecord(const std::string& layerName);
+    // If SF skips or rejects a buffer, remove the corresponding TimeRecord.
     void removeTimeRecord(const std::string& layerName, uint64_t frameNumber);
 
 private:
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp b/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
index 21f3ef3..b7b2778 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
+++ b/services/surfaceflinger/TimeStats/timestatsproto/TimeStatsHelper.cpp
@@ -68,12 +68,11 @@
 }
 
 std::string TimeStatsHelper::TimeStatsLayer::toString() const {
-    std::string result = "";
+    std::string result = "\n";
     StringAppendF(&result, "layerName = %s\n", layerName.c_str());
     StringAppendF(&result, "packageName = %s\n", packageName.c_str());
-    StringAppendF(&result, "statsStart = %lld\n", static_cast<long long int>(statsStart));
-    StringAppendF(&result, "statsEnd = %lld\n", static_cast<long long int>(statsEnd));
-    StringAppendF(&result, "totalFrames= %d\n", totalFrames);
+    StringAppendF(&result, "totalFrames = %d\n", totalFrames);
+    StringAppendF(&result, "droppedFrames = %d\n", droppedFrames);
     auto iter = deltas.find("present2present");
     if (iter != deltas.end()) {
         StringAppendF(&result, "averageFPS = %.3f\n", 1000.0 / iter->second.averageTime());
@@ -90,10 +89,9 @@
     std::string result = "SurfaceFlinger TimeStats:\n";
     StringAppendF(&result, "statsStart = %lld\n", static_cast<long long int>(statsStart));
     StringAppendF(&result, "statsEnd = %lld\n", static_cast<long long int>(statsEnd));
-    StringAppendF(&result, "totalFrames= %d\n", totalFrames);
-    StringAppendF(&result, "missedFrames= %d\n", missedFrames);
-    StringAppendF(&result, "clientCompositionFrames= %d\n", clientCompositionFrames);
-    StringAppendF(&result, "TimeStats for each layer is as below:\n");
+    StringAppendF(&result, "totalFrames = %d\n", totalFrames);
+    StringAppendF(&result, "missedFrames = %d\n", missedFrames);
+    StringAppendF(&result, "clientCompositionFrames = %d\n", clientCompositionFrames);
     const auto dumpStats = generateDumpStats(maxLayers);
     for (auto& ele : dumpStats) {
         StringAppendF(&result, "%s", ele->toString().c_str());
@@ -106,15 +104,14 @@
     SFTimeStatsLayerProto layerProto;
     layerProto.set_layer_name(layerName);
     layerProto.set_package_name(packageName);
-    layerProto.set_stats_start(statsStart);
-    layerProto.set_stats_end(statsEnd);
     layerProto.set_total_frames(totalFrames);
+    layerProto.set_dropped_frames(droppedFrames);
     for (auto& ele : deltas) {
         SFTimeStatsDeltaProto* deltaProto = layerProto.add_deltas();
         deltaProto->set_delta_name(ele.first);
         for (auto& histEle : ele.second.hist) {
             SFTimeStatsHistogramBucketProto* histProto = deltaProto->add_histograms();
-            histProto->set_render_millis(histEle.first);
+            histProto->set_time_millis(histEle.first);
             histProto->set_frame_count(histEle.second);
         }
     }
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
index 1798555..99c891b 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
+++ b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
@@ -42,9 +42,8 @@
     public:
         std::string layerName;
         std::string packageName;
-        int64_t statsStart = 0;
-        int64_t statsEnd = 0;
         int32_t totalFrames = 0;
+        int32_t droppedFrames = 0;
         std::unordered_map<std::string, Histogram> deltas;
 
         std::string toString() const;
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto b/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
index f29fbd1..ab7527e 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
+++ b/services/surfaceflinger/TimeStats/timestatsproto/timestats.proto
@@ -20,46 +20,59 @@
 
 option optimize_for = LITE_RUNTIME;
 
+// //depot/google3/java/com/google/android/apps/graphics/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;" on google3 side.
+
+// Next tag: 7
 message SFTimeStatsGlobalProto {
-  // The start & end timestamps in UTC as
-  // milliseconds since January 1, 1970
+  // The stats start time in UTC as seconds since January 1, 1970
   optional int64 stats_start = 1;
+  // The stats end time in UTC as seconds since January 1, 1970
   optional int64 stats_end = 2;
-  // Total frames
+  // Total number of frames presented during tracing period.
   optional int32 total_frames = 3;
   // Total missed frames of SurfaceFlinger.
   optional int32 missed_frames = 4;
   // Total frames fallback to client composition.
   optional int32 client_composition_frames = 5;
-
+  // Stats per layer. Apps could have multiple layers.
   repeated SFTimeStatsLayerProto stats = 6;
 }
 
+// Next tag: 8
 message SFTimeStatsLayerProto {
-  // The layer name
+  // The name of the visible view layer.
   optional string layer_name = 1;
-  // The package name
+  // The package name of the application owning this layer.
   optional string package_name = 2;
-  // The start & end timestamps in UTC as
-  // milliseconds since January 1, 1970
+  // The stats start time in UTC as seconds since January 1, 1970
   optional int64 stats_start = 3;
+  // The stats end time in UTC as seconds since January 1, 1970
   optional int64 stats_end = 4;
-  // Distinct frame count.
+  // Total number of frames presented during tracing period.
   optional int32 total_frames = 5;
-
+  // Total number of frames dropped by SurfaceFlinger.
+  optional int32 dropped_frames = 7;
+  // There are multiple timestamps tracked in SurfaceFlinger, and these are the
+  // histograms of deltas between different combinations of those timestamps.
   repeated SFTimeStatsDeltaProto deltas = 6;
 }
 
+// Next tag: 3
 message SFTimeStatsDeltaProto {
   // Name of the time interval
   optional string delta_name = 1;
-  // Histogram of the delta time
+  // Histogram of the delta time. There should be at most 85 buckets ranging
+  // from [0ms, 1ms) to [1000ms, infinity)
   repeated SFTimeStatsHistogramBucketProto histograms = 2;
 }
 
+// Next tag: 3
 message SFTimeStatsHistogramBucketProto {
-  // Lower bound of render time in milliseconds.
-  optional int32 render_millis = 1;
+  // Lower bound of time interval in milliseconds.
+  optional int32 time_millis = 1;
   // Number of frames in the bucket.
   optional int32 frame_count = 2;
 }