Remove event thread connection metric.

It's not an actionable metric and is causing performance problems due to
lock contention. So, remove the code.

Bug: 170661858
Test: builds
Change-Id: I70fc2772d2cfa1c8364775427b1e8f08ce4ca0ff
diff --git a/services/surfaceflinger/Scheduler/EventThread.cpp b/services/surfaceflinger/Scheduler/EventThread.cpp
index 281b0ae..c70ed2c 100644
--- a/services/surfaceflinger/Scheduler/EventThread.cpp
+++ b/services/surfaceflinger/Scheduler/EventThread.cpp
@@ -427,11 +427,6 @@
     mCondition.notify_all();
 }
 
-size_t EventThread::getEventThreadConnectionCount() {
-    std::lock_guard<std::mutex> lock(mMutex);
-    return mDisplayEventConnections.size();
-}
-
 void EventThread::threadMain(std::unique_lock<std::mutex>& lock) {
     DisplayEventConsumers consumers;
 
diff --git a/services/surfaceflinger/Scheduler/EventThread.h b/services/surfaceflinger/Scheduler/EventThread.h
index 684745b..7023445 100644
--- a/services/surfaceflinger/Scheduler/EventThread.h
+++ b/services/surfaceflinger/Scheduler/EventThread.h
@@ -131,9 +131,6 @@
     virtual VsyncEventData getLatestVsyncEventData(
             const sp<EventThreadConnection>& connection) const = 0;
 
-    // Retrieves the number of event connections tracked by this EventThread.
-    virtual size_t getEventThreadConnectionCount() = 0;
-
     virtual void onNewVsyncSchedule(std::shared_ptr<scheduler::VsyncSchedule>) = 0;
 };
 
@@ -172,8 +169,6 @@
     void setDuration(std::chrono::nanoseconds workDuration,
                      std::chrono::nanoseconds readyDuration) override;
 
-    size_t getEventThreadConnectionCount() override;
-
     void onNewVsyncSchedule(std::shared_ptr<scheduler::VsyncSchedule>) override EXCLUDES(mMutex);
 
 private:
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 0a1bd4c..08667bf 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -393,12 +393,6 @@
     thread->onModeChanged(mode);
 }
 
-size_t Scheduler::getEventThreadConnectionCount(ConnectionHandle handle) {
-    std::lock_guard<std::mutex> lock(mConnectionsLock);
-    RETURN_IF_INVALID_HANDLE(handle, 0);
-    return mConnections[handle].thread->getEventThreadConnectionCount();
-}
-
 void Scheduler::dump(ConnectionHandle handle, std::string& result) const {
     android::EventThread* thread;
     {
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index c44c447..0ffa2d2 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -278,8 +278,6 @@
     // Notifies the scheduler when the display size has changed. Called from SF's main thread
     void onActiveDisplayAreaChanged(uint32_t displayArea);
 
-    size_t getEventThreadConnectionCount(ConnectionHandle handle);
-
     // Stores the preferred refresh rate that an app should run at.
     // FrameRateOverride.refreshRateHz == 0 means no preference.
     void setPreferredRefreshRateForUid(FrameRateOverride);
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 2782ce4..8c53c42 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3002,10 +3002,6 @@
         }
     }
 
-    const size_t sfConnections = mScheduler->getEventThreadConnectionCount(mSfConnectionHandle);
-    const size_t appConnections = mScheduler->getEventThreadConnectionCount(mAppConnectionHandle);
-    mTimeStats->recordDisplayEventConnectionCount(sfConnections + appConnections);
-
     if (isDisplayConnected && !defaultDisplay->isPoweredOn()) {
         getRenderEngine().cleanupPostRender();
         return;
diff --git a/services/surfaceflinger/TimeStats/TimeStats.cpp b/services/surfaceflinger/TimeStats/TimeStats.cpp
index 630cef1..368cb41 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.cpp
+++ b/services/surfaceflinger/TimeStats/TimeStats.cpp
@@ -106,7 +106,8 @@
         atom->set_client_composition_frames(mTimeStats.clientCompositionFramesLegacy);
         atom->set_display_on_millis(mTimeStats.displayOnTimeLegacy);
         atom->set_animation_millis(mTimeStats.presentToPresentLegacy.totalTime());
-        atom->set_event_connection_count(mTimeStats.displayEventConnectionsCountLegacy);
+        // Deprecated
+        atom->set_event_connection_count(0);
         *atom->mutable_frame_duration() =
                 histogramToProto(mTimeStats.frameDurationLegacy.hist, mMaxPulledHistogramBuckets);
         *atom->mutable_render_engine_timing() =
@@ -356,16 +357,6 @@
     mTimeStats.refreshRateSwitchesLegacy++;
 }
 
-void TimeStats::recordDisplayEventConnectionCount(int32_t count) {
-    if (!mEnabled.load()) return;
-
-    ATRACE_CALL();
-
-    std::lock_guard<std::mutex> lock(mMutex);
-    mTimeStats.displayEventConnectionsCountLegacy =
-            std::max(mTimeStats.displayEventConnectionsCountLegacy, count);
-}
-
 static int32_t toMs(nsecs_t nanos) {
     int64_t millis =
             std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::nanoseconds(nanos))
@@ -1072,7 +1063,6 @@
     mTimeStats.compositionStrategyPredictedLegacy = 0;
     mTimeStats.compositionStrategyPredictionSucceededLegacy = 0;
     mTimeStats.refreshRateSwitchesLegacy = 0;
-    mTimeStats.displayEventConnectionsCountLegacy = 0;
     mTimeStats.displayOnTimeLegacy = 0;
     mTimeStats.presentToPresentLegacy.hist.clear();
     mTimeStats.frameDurationLegacy.hist.clear();
diff --git a/services/surfaceflinger/TimeStats/TimeStats.h b/services/surfaceflinger/TimeStats/TimeStats.h
index 5f58657..0c227d4 100644
--- a/services/surfaceflinger/TimeStats/TimeStats.h
+++ b/services/surfaceflinger/TimeStats/TimeStats.h
@@ -57,9 +57,6 @@
     virtual void incrementMissedFrames() = 0;
     // Increments the number of times the display refresh rate changed.
     virtual void incrementRefreshRateSwitches() = 0;
-    // Records the most up-to-date count of display event connections.
-    // The stored count will be the maximum ever recoded.
-    virtual void recordDisplayEventConnectionCount(int32_t count) = 0;
 
     // Records the start and end times for a frame.
     // The start time is the same as the beginning of a SurfaceFlinger
@@ -253,7 +250,6 @@
     void incrementTotalFrames() override;
     void incrementMissedFrames() override;
     void incrementRefreshRateSwitches() override;
-    void recordDisplayEventConnectionCount(int32_t count) override;
 
     void recordFrameDuration(nsecs_t startTime, nsecs_t endTime) override;
     void recordRenderEngineDuration(nsecs_t startTime, nsecs_t endTime) override;
diff --git a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
index 60aa810..9e97f0d 100644
--- a/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
+++ b/services/surfaceflinger/TimeStats/timestatsproto/include/timestatsproto/TimeStatsHelper.h
@@ -175,7 +175,6 @@
         int32_t clientCompositionReusedFramesLegacy = 0;
         int32_t refreshRateSwitchesLegacy = 0;
         int32_t compositionStrategyChangesLegacy = 0;
-        int32_t displayEventConnectionsCountLegacy = 0;
         int64_t displayOnTimeLegacy = 0;
         Histogram presentToPresentLegacy;
         Histogram frameDurationLegacy;
diff --git a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
index 5fed9b4..91c6239 100644
--- a/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
+++ b/services/surfaceflinger/tests/unittests/EventThreadTest.cpp
@@ -634,31 +634,6 @@
     expectVSyncCallbackScheduleReceived(false);
 }
 
-TEST_F(EventThreadTest, tracksEventConnections) {
-    setupEventThread(VSYNC_PERIOD);
-
-    EXPECT_EQ(2, mThread->getEventThreadConnectionCount());
-    ConnectionEventRecorder errorConnectionEventRecorder{NO_MEMORY};
-    sp<MockEventThreadConnection> errorConnection = createConnection(errorConnectionEventRecorder);
-    mThread->setVsyncRate(1, errorConnection);
-    EXPECT_EQ(3, mThread->getEventThreadConnectionCount());
-    ConnectionEventRecorder secondConnectionEventRecorder{0};
-    sp<MockEventThreadConnection> secondConnection =
-            createConnection(secondConnectionEventRecorder);
-    mThread->setVsyncRate(1, secondConnection);
-    EXPECT_EQ(4, mThread->getEventThreadConnectionCount());
-
-    // EventThread should enable vsync callbacks.
-    expectVSyncCallbackScheduleReceived(true);
-
-    // The first event will be seen by the connection, which then returns an error.
-    onVSyncEvent(123, 456, 789);
-    expectVsyncEventReceivedByConnection("errorConnection", errorConnectionEventRecorder, 123, 1u);
-    expectVsyncEventReceivedByConnection("successConnection", secondConnectionEventRecorder, 123,
-                                         1u);
-    EXPECT_EQ(3, mThread->getEventThreadConnectionCount());
-}
-
 TEST_F(EventThreadTest, eventsDroppedIfNonfatalEventDeliveryError) {
     setupEventThread(VSYNC_PERIOD);
 
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index 405f79d..3200003 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -158,10 +158,6 @@
 
     EXPECT_CALL(*mEventThread, setDuration(10ns, 20ns)).Times(1);
     mScheduler->setDuration(mConnectionHandle, 10ns, 20ns);
-
-    static constexpr size_t kEventConnections = 5;
-    EXPECT_CALL(*mEventThread, getEventThreadConnectionCount()).WillOnce(Return(kEventConnections));
-    EXPECT_EQ(kEventConnections, mScheduler->getEventThreadConnectionCount(mConnectionHandle));
 }
 
 TEST_F(SchedulerTest, registerDisplay) FTL_FAKE_GUARD(kMainThreadContext) {
diff --git a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
index a9ae1d3..86ed233 100644
--- a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
+++ b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
@@ -1079,7 +1079,6 @@
     constexpr size_t TOTAL_FRAMES = 5;
     constexpr size_t MISSED_FRAMES = 4;
     constexpr size_t CLIENT_COMPOSITION_FRAMES = 3;
-    constexpr size_t DISPLAY_EVENT_CONNECTIONS = 14;
     constexpr nsecs_t DISPLAY_DEADLINE_DELTA = 1'000'000;
     constexpr nsecs_t DISPLAY_PRESENT_JITTER = 2'000'000;
     constexpr nsecs_t APP_DEADLINE_DELTA = 3'000'000;
@@ -1100,7 +1099,6 @@
 
     insertTimeRecord(NORMAL_SEQUENCE, LAYER_ID_0, 1, 1000000);
 
-    mTimeStats->recordDisplayEventConnectionCount(DISPLAY_EVENT_CONNECTIONS);
     mTimeStats->setPowerMode(PowerMode::ON);
     mTimeStats->recordFrameDuration(1000000, 3000000);
     mTimeStats->recordRenderEngineDuration(2000000, 4000000);
@@ -1157,7 +1155,6 @@
     EXPECT_EQ(atom.client_composition_frames(), CLIENT_COMPOSITION_FRAMES);
     // Display on millis is not checked.
     EXPECT_EQ(atom.animation_millis(), 2);
-    EXPECT_EQ(atom.event_connection_count(), DISPLAY_EVENT_CONNECTIONS);
     EXPECT_THAT(atom.frame_duration(), HistogramEq(buildExpectedHistogram({2}, {1})));
     EXPECT_THAT(atom.render_engine_timing(), HistogramEq(buildExpectedHistogram({1, 2}, {1, 1})));
     EXPECT_EQ(atom.total_timeline_frames(), 9);
diff --git a/services/surfaceflinger/tests/unittests/mock/MockEventThread.h b/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
index 8d57049..9a1a16d 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockEventThread.h
@@ -49,7 +49,6 @@
                 (const sp<android::EventThreadConnection>&), (const, override));
     MOCK_METHOD(void, requestLatestConfig, (const sp<android::EventThreadConnection>&));
     MOCK_METHOD(void, pauseVsyncCallback, (bool));
-    MOCK_METHOD(size_t, getEventThreadConnectionCount, (), (override));
     MOCK_METHOD(void, onNewVsyncSchedule, (std::shared_ptr<scheduler::VsyncSchedule>), (override));
 };
 
diff --git a/services/surfaceflinger/tests/unittests/mock/MockTimeStats.h b/services/surfaceflinger/tests/unittests/mock/MockTimeStats.h
index 86fbadc..c82e45b 100644
--- a/services/surfaceflinger/tests/unittests/mock/MockTimeStats.h
+++ b/services/surfaceflinger/tests/unittests/mock/MockTimeStats.h
@@ -34,7 +34,6 @@
     MOCK_METHOD0(incrementTotalFrames, void());
     MOCK_METHOD0(incrementMissedFrames, void());
     MOCK_METHOD0(incrementRefreshRateSwitches, void());
-    MOCK_METHOD1(recordDisplayEventConnectionCount, void(int32_t));
     MOCK_METHOD2(recordFrameDuration, void(nsecs_t, nsecs_t));
     MOCK_METHOD2(recordRenderEngineDuration, void(nsecs_t, nsecs_t));
     MOCK_METHOD2(recordRenderEngineDuration, void(nsecs_t, const std::shared_ptr<FenceTime>&));