SF: use CLOCK_BOOTTIME for frame timeline

Using CLOCK_BOOTTIME avoids the need to resync CLOCK_MONOTONIC in
perfetto after suspend.

Bug: 185346474
Test: Collect perfetto traces and observe timeline slices
Change-Id: Ifda1fb43c6ac205ec60cb331c139e950a24a60cb
diff --git a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
index 81747d5..ec59888 100644
--- a/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
+++ b/services/surfaceflinger/FrameTimeline/FrameTimeline.cpp
@@ -618,15 +618,15 @@
     }
 }
 
-void SurfaceFrame::tracePredictions(int64_t displayFrameToken) const {
+void SurfaceFrame::tracePredictions(int64_t displayFrameToken, nsecs_t monoBootOffset) const {
     int64_t expectedTimelineCookie = mTraceCookieCounter.getCookieForTracing();
 
     // Expected timeline start
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         std::scoped_lock lock(mMutex);
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mPredictions.startTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(static_cast<uint64_t>(mPredictions.startTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* expectedSurfaceFrameStartEvent = event->set_expected_surface_frame_start();
@@ -644,8 +644,8 @@
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         std::scoped_lock lock(mMutex);
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mPredictions.endTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(static_cast<uint64_t>(mPredictions.endTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* expectedSurfaceFrameEndEvent = event->set_frame_end();
@@ -654,14 +654,14 @@
     });
 }
 
-void SurfaceFrame::traceActuals(int64_t displayFrameToken) const {
+void SurfaceFrame::traceActuals(int64_t displayFrameToken, nsecs_t monoBootOffset) const {
     int64_t actualTimelineCookie = mTraceCookieCounter.getCookieForTracing();
 
     // Actual timeline start
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         std::scoped_lock lock(mMutex);
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
         // Actual start time is not yet available, so use expected start instead
         if (mPredictionState == PredictionState::Expired) {
             // If prediction is expired, we can't use the predicted start time. Instead, just use a
@@ -669,11 +669,12 @@
             // frame in the trace.
             nsecs_t endTime =
                     (mPresentState == PresentState::Dropped ? mDropTime : mActuals.endTime);
-            packet->set_timestamp(
-                    static_cast<uint64_t>(endTime - kPredictionExpiredStartTimeDelta));
+            packet->set_timestamp(static_cast<uint64_t>(endTime - kPredictionExpiredStartTimeDelta +
+                                                        monoBootOffset));
         } else {
-            packet->set_timestamp(static_cast<uint64_t>(
-                    mActuals.startTime == 0 ? mPredictions.startTime : mActuals.startTime));
+            packet->set_timestamp(static_cast<uint64_t>(monoBootOffset + mActuals.startTime == 0
+                                                                ? mPredictions.startTime
+                                                                : mActuals.startTime));
         }
 
         auto* event = packet->set_frame_timeline_event();
@@ -706,11 +707,11 @@
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         std::scoped_lock lock(mMutex);
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
         if (mPresentState == PresentState::Dropped) {
-            packet->set_timestamp(static_cast<uint64_t>(mDropTime));
+            packet->set_timestamp(static_cast<uint64_t>(mDropTime + monoBootOffset));
         } else {
-            packet->set_timestamp(static_cast<uint64_t>(mActuals.endTime));
+            packet->set_timestamp(static_cast<uint64_t>(mActuals.endTime + monoBootOffset));
         }
 
         auto* event = packet->set_frame_timeline_event();
@@ -723,7 +724,7 @@
 /**
  * TODO(b/178637512): add inputEventId to the perfetto trace.
  */
-void SurfaceFrame::trace(int64_t displayFrameToken) const {
+void SurfaceFrame::trace(int64_t displayFrameToken, nsecs_t monoBootOffset) const {
     if (mToken == FrameTimelineInfo::INVALID_VSYNC_ID ||
         displayFrameToken == FrameTimelineInfo::INVALID_VSYNC_ID) {
         // No packets can be traced with a missing token.
@@ -732,9 +733,9 @@
     if (getPredictionState() != PredictionState::Expired) {
         // Expired predictions have zeroed timestamps. This cannot be used in any meaningful way in
         // a trace.
-        tracePredictions(displayFrameToken);
+        tracePredictions(displayFrameToken, monoBootOffset);
     }
-    traceActuals(displayFrameToken);
+    traceActuals(displayFrameToken, monoBootOffset);
 }
 
 namespace impl {
@@ -760,8 +761,9 @@
 }
 
 FrameTimeline::FrameTimeline(std::shared_ptr<TimeStats> timeStats, pid_t surfaceFlingerPid,
-                             JankClassificationThresholds thresholds)
-      : mMaxDisplayFrames(kDefaultMaxDisplayFrames),
+                             JankClassificationThresholds thresholds, bool useBootTimeClock)
+      : mUseBootTimeClock(useBootTimeClock),
+        mMaxDisplayFrames(kDefaultMaxDisplayFrames),
         mTimeStats(std::move(timeStats)),
         mSurfaceFlingerPid(surfaceFlingerPid),
         mJankClassificationThresholds(thresholds) {
@@ -1016,14 +1018,16 @@
     }
 }
 
-void FrameTimeline::DisplayFrame::tracePredictions(pid_t surfaceFlingerPid) const {
+void FrameTimeline::DisplayFrame::tracePredictions(pid_t surfaceFlingerPid,
+                                                   nsecs_t monoBootOffset) const {
     int64_t expectedTimelineCookie = mTraceCookieCounter.getCookieForTracing();
 
     // Expected timeline start
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mSurfaceFlingerPredictions.startTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(
+                static_cast<uint64_t>(mSurfaceFlingerPredictions.startTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* expectedDisplayFrameStartEvent = event->set_expected_display_frame_start();
@@ -1037,8 +1041,9 @@
     // Expected timeline end
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mSurfaceFlingerPredictions.endTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(
+                static_cast<uint64_t>(mSurfaceFlingerPredictions.endTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* expectedDisplayFrameEndEvent = event->set_frame_end();
@@ -1047,14 +1052,16 @@
     });
 }
 
-void FrameTimeline::DisplayFrame::traceActuals(pid_t surfaceFlingerPid) const {
+void FrameTimeline::DisplayFrame::traceActuals(pid_t surfaceFlingerPid,
+                                               nsecs_t monoBootOffset) const {
     int64_t actualTimelineCookie = mTraceCookieCounter.getCookieForTracing();
 
     // Actual timeline start
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mSurfaceFlingerActuals.startTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(
+                static_cast<uint64_t>(mSurfaceFlingerActuals.startTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* actualDisplayFrameStartEvent = event->set_actual_display_frame_start();
@@ -1075,8 +1082,9 @@
     // Actual timeline end
     FrameTimelineDataSource::Trace([&](FrameTimelineDataSource::TraceContext ctx) {
         auto packet = ctx.NewTracePacket();
-        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_MONOTONIC);
-        packet->set_timestamp(static_cast<uint64_t>(mSurfaceFlingerActuals.presentTime));
+        packet->set_timestamp_clock_id(perfetto::protos::pbzero::BUILTIN_CLOCK_BOOTTIME);
+        packet->set_timestamp(
+                static_cast<uint64_t>(mSurfaceFlingerActuals.presentTime + monoBootOffset));
 
         auto* event = packet->set_frame_timeline_event();
         auto* actualDisplayFrameEndEvent = event->set_frame_end();
@@ -1085,7 +1093,7 @@
     });
 }
 
-void FrameTimeline::DisplayFrame::trace(pid_t surfaceFlingerPid) const {
+void FrameTimeline::DisplayFrame::trace(pid_t surfaceFlingerPid, nsecs_t monoBootOffset) const {
     if (mToken == FrameTimelineInfo::INVALID_VSYNC_ID) {
         // DisplayFrame should not have an invalid token.
         ALOGE("Cannot trace DisplayFrame with invalid token");
@@ -1095,12 +1103,12 @@
     if (mPredictionState == PredictionState::Valid) {
         // Expired and unknown predictions have zeroed timestamps. This cannot be used in any
         // meaningful way in a trace.
-        tracePredictions(surfaceFlingerPid);
+        tracePredictions(surfaceFlingerPid, monoBootOffset);
     }
-    traceActuals(surfaceFlingerPid);
+    traceActuals(surfaceFlingerPid, monoBootOffset);
 
     for (auto& surfaceFrame : mSurfaceFrames) {
-        surfaceFrame->trace(mToken);
+        surfaceFrame->trace(mToken, monoBootOffset);
     }
 }
 
@@ -1164,6 +1172,12 @@
 }
 
 void FrameTimeline::flushPendingPresentFences() {
+    // Perfetto is using boottime clock to void drifts when the device goes
+    // to suspend.
+    const auto monoBootOffset = mUseBootTimeClock
+            ? (systemTime(SYSTEM_TIME_BOOTTIME) - systemTime(SYSTEM_TIME_MONOTONIC))
+            : 0;
+
     for (size_t i = 0; i < mPendingPresentFences.size(); i++) {
         const auto& pendingPresentFence = mPendingPresentFences[i];
         nsecs_t signalTime = Fence::SIGNAL_TIME_INVALID;
@@ -1175,7 +1189,7 @@
         }
         auto& displayFrame = pendingPresentFence.second;
         displayFrame->onPresent(signalTime, mPreviousPresentTime);
-        displayFrame->trace(mSurfaceFlingerPid);
+        displayFrame->trace(mSurfaceFlingerPid, monoBootOffset);
         mPreviousPresentTime = signalTime;
 
         mPendingPresentFences.erase(mPendingPresentFences.begin() + static_cast<int>(i));
diff --git a/services/surfaceflinger/FrameTimeline/FrameTimeline.h b/services/surfaceflinger/FrameTimeline/FrameTimeline.h
index 36d6290..a2305af 100644
--- a/services/surfaceflinger/FrameTimeline/FrameTimeline.h
+++ b/services/surfaceflinger/FrameTimeline/FrameTimeline.h
@@ -204,8 +204,9 @@
     std::string miniDump() const;
     // Emits a packet for perfetto tracing. The function body will be executed only if tracing is
     // enabled. The displayFrameToken is needed to link the SurfaceFrame to the corresponding
-    // DisplayFrame at the trace processor side.
-    void trace(int64_t displayFrameToken) const;
+    // DisplayFrame at the trace processor side. monoBootOffset is the difference
+    // between SYSTEM_TIME_BOOTTIME and SYSTEM_TIME_MONOTONIC.
+    void trace(int64_t displayFrameToken, nsecs_t monoBootOffset) const;
 
     // Getter functions used only by FrameTimelineTests and SurfaceFrame internally
     TimelineItem getActuals() const;
@@ -225,8 +226,8 @@
             std::chrono::duration_cast<std::chrono::nanoseconds>(2ms).count();
 
 private:
-    void tracePredictions(int64_t displayFrameToken) const;
-    void traceActuals(int64_t displayFrameToken) const;
+    void tracePredictions(int64_t displayFrameToken, nsecs_t monoBootOffset) const;
+    void traceActuals(int64_t displayFrameToken, nsecs_t monoBootOffset) const;
     void classifyJankLocked(int32_t displayFrameJankType, const Fps& refreshRate,
                             nsecs_t& deadlineDelta) REQUIRES(mMutex);
 
@@ -369,8 +370,9 @@
         // Dumpsys interface - dumps all data irrespective of jank
         void dumpAll(std::string& result, nsecs_t baseTime) const;
         // Emits a packet for perfetto tracing. The function body will be executed only if tracing
-        // is enabled.
-        void trace(pid_t surfaceFlingerPid) const;
+        // is enabled. monoBootOffset is the difference between SYSTEM_TIME_BOOTTIME
+        // and SYSTEM_TIME_MONOTONIC.
+        void trace(pid_t surfaceFlingerPid, nsecs_t monoBootOffset) const;
         // Sets the token, vsyncPeriod, predictions and SF start time.
         void onSfWakeUp(int64_t token, Fps refreshRate, std::optional<TimelineItem> predictions,
                         nsecs_t wakeUpTime);
@@ -401,8 +403,8 @@
 
     private:
         void dump(std::string& result, nsecs_t baseTime) const;
-        void tracePredictions(pid_t surfaceFlingerPid) const;
-        void traceActuals(pid_t surfaceFlingerPid) const;
+        void tracePredictions(pid_t surfaceFlingerPid, nsecs_t monoBootOffset) const;
+        void traceActuals(pid_t surfaceFlingerPid, nsecs_t monoBootOffset) const;
         void classifyJank(nsecs_t& deadlineDelta, nsecs_t& deltaToVsync,
                           nsecs_t previousPresentTime);
 
@@ -442,7 +444,7 @@
     };
 
     FrameTimeline(std::shared_ptr<TimeStats> timeStats, pid_t surfaceFlingerPid,
-                  JankClassificationThresholds thresholds = {});
+                  JankClassificationThresholds thresholds = {}, bool useBootTimeClock = true);
     ~FrameTimeline() = default;
 
     frametimeline::TokenManager* getTokenManager() override { return &mTokenManager; }
@@ -484,6 +486,7 @@
     TokenManager mTokenManager;
     TraceCookieCounter mTraceCookieCounter;
     mutable std::mutex mMutex;
+    const bool mUseBootTimeClock;
     uint32_t mMaxDisplayFrames;
     std::shared_ptr<TimeStats> mTimeStats;
     const pid_t mSurfaceFlingerPid;
diff --git a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
index 834a560..f1efa92 100644
--- a/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
+++ b/services/surfaceflinger/tests/unittests/FrameTimelineTest.cpp
@@ -66,9 +66,10 @@
     }
 
     void SetUp() override {
+        constexpr bool kUseBootTimeClock = true;
         mTimeStats = std::make_shared<mock::TimeStats>();
         mFrameTimeline = std::make_unique<impl::FrameTimeline>(mTimeStats, kSurfaceFlingerPid,
-                                                               kTestThresholds);
+                                                               kTestThresholds, !kUseBootTimeClock);
         mFrameTimeline->registerDataSource();
         mTokenManager = &mFrameTimeline->mTokenManager;
         mTraceCookieCounter = &mFrameTimeline->mTraceCookieCounter;