Merge "SF: Suppress frame rate when small area updating" into main
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 50f24a7..8f785a0 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -3212,6 +3212,14 @@
     }
 
     mDrawingState.releaseBufferEndpoint = bufferData.releaseBufferEndpoint;
+
+    // If the layer had been updated a TextureView, this would make sure the present time could be
+    // same to TextureView update when it's a small dirty, and get the correct heuristic rate.
+    if (mFlinger->mScheduler->supportSmallDirtyDetection()) {
+        if (mDrawingState.useVsyncIdForRefreshRateSelection) {
+            mUsedVsyncIdForRefreshRateSelection = true;
+        }
+    }
     return true;
 }
 
@@ -3234,10 +3242,38 @@
                             mDrawingState.latchedVsyncId);
             if (prediction.has_value()) {
                 ATRACE_FORMAT_INSTANT("predictedPresentTime");
+                mMaxTimeForUseVsyncId = prediction->presentTime +
+                        scheduler::LayerHistory::kMaxPeriodForHistory.count();
                 return prediction->presentTime;
             }
         }
 
+        if (!mFlinger->mScheduler->supportSmallDirtyDetection()) {
+            return static_cast<nsecs_t>(0);
+        }
+
+        // If the layer is not an application and didn't set an explicit rate or desiredPresentTime,
+        // return "0" to tell the layer history that it will use the max refresh rate without
+        // calculating the adaptive rate.
+        if (mWindowType != WindowInfo::Type::APPLICATION &&
+            mWindowType != WindowInfo::Type::BASE_APPLICATION) {
+            return static_cast<nsecs_t>(0);
+        }
+
+        // Return the valid present time only when the layer potentially updated a TextureView so
+        // LayerHistory could heuristically calculate the rate if the UI is continually updating.
+        if (mUsedVsyncIdForRefreshRateSelection) {
+            const auto prediction =
+                    mFlinger->mFrameTimeline->getTokenManager()->getPredictionsForToken(
+                            mDrawingState.latchedVsyncId);
+            if (prediction.has_value()) {
+                if (mMaxTimeForUseVsyncId >= prediction->presentTime) {
+                    return prediction->presentTime;
+                }
+                mUsedVsyncIdForRefreshRateSelection = false;
+            }
+        }
+
         return static_cast<nsecs_t>(0);
     }();
 
@@ -3297,6 +3333,7 @@
     mDrawingState.surfaceDamageRegion = surfaceDamage;
     mDrawingState.modified = true;
     setTransactionFlags(eTransactionNeeded);
+    setIsSmallDirty();
     return true;
 }
 
@@ -4335,6 +4372,25 @@
     mLastLatchTime = latchTime;
 }
 
+void Layer::setIsSmallDirty() {
+    if (!mFlinger->mScheduler->supportSmallDirtyDetection()) {
+        return;
+    }
+
+    if (mWindowType != WindowInfo::Type::APPLICATION &&
+        mWindowType != WindowInfo::Type::BASE_APPLICATION) {
+        return;
+    }
+    Rect bounds = mDrawingState.surfaceDamageRegion.getBounds();
+    if (!bounds.isValid()) {
+        return;
+    }
+
+    // If the damage region is a small dirty, this could give the hint for the layer history that
+    // it could suppress the heuristic rate when calculating.
+    mSmallDirty = mFlinger->mScheduler->isSmallDirtyArea(bounds.getWidth() * bounds.getHeight());
+}
+
 } // namespace android
 
 #if defined(__gl_h_)
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 1f2485f..7b6c56b 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -841,6 +841,14 @@
     mutable bool contentDirty{false};
     Region surfaceDamageRegion;
 
+    // True when the surfaceDamageRegion is recognized as a small area update.
+    bool mSmallDirty{false};
+    // Used to check if mUsedVsyncIdForRefreshRateSelection should be expired when it stop updating.
+    nsecs_t mMaxTimeForUseVsyncId = 0;
+    // True when DrawState.useVsyncIdForRefreshRateSelection previously set to true during updating
+    // buffer.
+    bool mUsedVsyncIdForRefreshRateSelection{false};
+
     // Layer serial number.  This gives layers an explicit ordering, so we
     // have a stable sort order when their layer stack and Z-order are
     // the same.
@@ -903,6 +911,7 @@
                 .transform = getTransform(),
                 .setFrameRateVote = getFrameRateForLayerTree(),
                 .frameRateSelectionPriority = getFrameRateSelectionPriority(),
+                .isSmallDirty = mSmallDirty,
         };
     };
     bool hasBuffer() const { return mBufferInfo.mBuffer != nullptr; }
@@ -917,6 +926,9 @@
     // Exposed so SurfaceFlinger can assert that it's held
     const sp<SurfaceFlinger> mFlinger;
 
+    // Check if the damage region is a small dirty.
+    void setIsSmallDirty();
+
 protected:
     // For unit tests
     friend class TestableSurfaceFlinger;
diff --git a/services/surfaceflinger/Scheduler/LayerHistory.cpp b/services/surfaceflinger/Scheduler/LayerHistory.cpp
index 565a490..13cf764 100644
--- a/services/surfaceflinger/Scheduler/LayerHistory.cpp
+++ b/services/surfaceflinger/Scheduler/LayerHistory.cpp
@@ -306,4 +306,11 @@
     return {LayerStatus::NotFound, nullptr};
 }
 
+bool LayerHistory::isSmallDirtyArea(uint32_t dirtyArea) const {
+    const float ratio = (float)dirtyArea / mDisplayArea;
+    const bool isSmallDirty = ratio <= kSmallDirtyArea;
+    ATRACE_FORMAT_INSTANT("small dirty=%s, ratio=%.3f", isSmallDirty ? "true" : "false", ratio);
+    return isSmallDirty;
+}
+
 } // namespace android::scheduler
diff --git a/services/surfaceflinger/Scheduler/LayerHistory.h b/services/surfaceflinger/Scheduler/LayerHistory.h
index d083fa2..562bb4c 100644
--- a/services/surfaceflinger/Scheduler/LayerHistory.h
+++ b/services/surfaceflinger/Scheduler/LayerHistory.h
@@ -43,6 +43,7 @@
 class LayerHistory {
 public:
     using LayerVoteType = RefreshRateSelector::LayerVoteType;
+    static constexpr std::chrono::nanoseconds kMaxPeriodForHistory = 1s;
 
     LayerHistory();
     ~LayerHistory();
@@ -84,10 +85,14 @@
     // return the frames per second of the layer with the given sequence id.
     float getLayerFramerate(nsecs_t now, int32_t id) const;
 
+    bool isSmallDirtyArea(uint32_t dirtyArea) const;
+
 private:
     friend class LayerHistoryTest;
     friend class TestableScheduler;
 
+    static constexpr float kSmallDirtyArea = 0.07f;
+
     using LayerPair = std::pair<Layer*, std::unique_ptr<LayerInfo>>;
     // keyed by id as returned from Layer::getSequence()
     using LayerInfos = std::unordered_map<int32_t, LayerPair>;
diff --git a/services/surfaceflinger/Scheduler/LayerInfo.cpp b/services/surfaceflinger/Scheduler/LayerInfo.cpp
index 750803b..e4df494 100644
--- a/services/surfaceflinger/Scheduler/LayerInfo.cpp
+++ b/services/surfaceflinger/Scheduler/LayerInfo.cpp
@@ -65,7 +65,8 @@
         case LayerUpdateType::Buffer:
             FrameTimeData frameTime = {.presentTime = lastPresentTime,
                                        .queueTime = mLastUpdatedTime,
-                                       .pendingModeChange = pendingModeChange};
+                                       .pendingModeChange = pendingModeChange,
+                                       .isSmallDirty = props.isSmallDirty};
             mFrameTimes.push_back(frameTime);
             if (mFrameTimes.size() > HISTORY_SIZE) {
                 mFrameTimes.pop_front();
@@ -101,11 +102,15 @@
     // classification.
     bool isFrequent = true;
     bool isInfrequent = true;
+    int32_t smallDirtyCount = 0;
     const auto n = mFrameTimes.size() - 1;
     for (size_t i = 0; i < kFrequentLayerWindowSize - 1; i++) {
         if (mFrameTimes[n - i].queueTime - mFrameTimes[n - i - 1].queueTime <
             kMaxPeriodForFrequentLayerNs.count()) {
             isInfrequent = false;
+            if (mFrameTimes[n - i].presentTime == 0 && mFrameTimes[n - i].isSmallDirty) {
+                smallDirtyCount++;
+            }
         } else {
             isFrequent = false;
         }
@@ -115,7 +120,8 @@
         // If the layer was previously inconclusive, we clear
         // the history as indeterminate layers changed to frequent,
         // and we should not look at the stale data.
-        return {isFrequent, isFrequent && !mIsFrequencyConclusive, /* isConclusive */ true};
+        return {isFrequent, isFrequent && !mIsFrequencyConclusive, /* isConclusive */ true,
+                /* isSmallDirty */ smallDirtyCount >= kNumSmallDirtyThreshold};
     }
 
     // If we can't determine whether the layer is frequent or not, we return
@@ -204,6 +210,7 @@
 
     nsecs_t totalDeltas = 0;
     int numDeltas = 0;
+    int32_t smallDirtyCount = 0;
     auto prevFrame = mFrameTimes.begin();
     for (auto it = mFrameTimes.begin() + 1; it != mFrameTimes.end(); ++it) {
         const auto currDelta = getFrameTime(*it) - getFrameTime(*prevFrame);
@@ -212,6 +219,13 @@
             continue;
         }
 
+        // If this is a small area update, we don't want to consider it for calculating the average
+        // frame time. Instead, we let the bigger frame updates to drive the calculation.
+        if (it->isSmallDirty && currDelta < kMinPeriodBetweenSmallDirtyFrames) {
+            smallDirtyCount++;
+            continue;
+        }
+
         prevFrame = it;
 
         if (currDelta > kMaxPeriodBetweenFrames) {
@@ -223,6 +237,10 @@
         numDeltas++;
     }
 
+    if (smallDirtyCount > 0) {
+        ATRACE_FORMAT_INSTANT("small dirty = %" PRIu32, smallDirtyCount);
+    }
+
     if (numDeltas == 0) {
         return std::nullopt;
     }
@@ -313,6 +331,14 @@
         clearHistory(now);
     }
 
+    // Return no vote if the latest frames are small dirty.
+    if (frequent.isSmallDirty && !mLastRefreshRate.reported.isValid()) {
+        ATRACE_FORMAT_INSTANT("NoVote (small dirty)");
+        ALOGV("%s is small dirty", mName.c_str());
+        votes.push_back({LayerHistory::LayerVoteType::NoVote, Fps()});
+        return votes;
+    }
+
     auto refreshRate = calculateRefreshRateIfPossible(selector, now);
     if (refreshRate.has_value()) {
         ALOGV("%s calculated refresh rate: %s", mName.c_str(), to_string(*refreshRate).c_str());
diff --git a/services/surfaceflinger/Scheduler/LayerInfo.h b/services/surfaceflinger/Scheduler/LayerInfo.h
index 7d2444c..1e08ec8 100644
--- a/services/surfaceflinger/Scheduler/LayerInfo.h
+++ b/services/surfaceflinger/Scheduler/LayerInfo.h
@@ -58,6 +58,7 @@
     static constexpr Fps kMinFpsForFrequentLayer = 10_Hz;
     static constexpr auto kMaxPeriodForFrequentLayerNs =
             std::chrono::nanoseconds(kMinFpsForFrequentLayer.getPeriodNsecs()) + 1ms;
+    static constexpr size_t kNumSmallDirtyThreshold = 2;
 
     friend class LayerHistoryTest;
     friend class LayerInfoTest;
@@ -235,6 +236,7 @@
         nsecs_t presentTime; // desiredPresentTime, if provided
         nsecs_t queueTime;  // buffer queue time
         bool pendingModeChange;
+        bool isSmallDirty;
     };
 
     // Holds information about the calculated and reported refresh rate
@@ -299,6 +301,8 @@
         bool clearHistory;
         // Represents whether we were able to determine isFrequent conclusively
         bool isConclusive;
+        // Represents whether the latest frames are small dirty.
+        bool isSmallDirty = false;
     };
     Frequent isFrequent(nsecs_t now) const;
     bool isAnimating(nsecs_t now) const;
@@ -317,6 +321,11 @@
     // this period apart from each other, the interval between them won't be
     // taken into account when calculating average frame rate.
     static constexpr nsecs_t kMaxPeriodBetweenFrames = kMinFpsForFrequentLayer.getPeriodNsecs();
+    // Used for sanitizing the heuristic data. If frames are small dirty updating and are less
+    // than this period apart from each other, the interval between them won't be
+    // taken into account when calculating average frame rate.
+    static constexpr nsecs_t kMinPeriodBetweenSmallDirtyFrames = (60_Hz).getPeriodNsecs();
+
     LayerHistory::LayerVoteType mDefaultVote;
 
     LayerVote mLayerVote;
@@ -331,7 +340,7 @@
     std::chrono::time_point<std::chrono::steady_clock> mFrameTimeValidSince =
             std::chrono::steady_clock::now();
     static constexpr size_t HISTORY_SIZE = RefreshRateHistory::HISTORY_SIZE;
-    static constexpr std::chrono::nanoseconds HISTORY_DURATION = 1s;
+    static constexpr std::chrono::nanoseconds HISTORY_DURATION = LayerHistory::kMaxPeriodForHistory;
 
     std::unique_ptr<LayerProps> mLayerProps;
 
@@ -349,6 +358,7 @@
     ui::Transform transform;
     LayerInfo::FrameRate setFrameRateVote;
     int32_t frameRateSelectionPriority = -1;
+    bool isSmallDirty = false;
 };
 
 } // namespace scheduler
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 85d0f9a..ec20610 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -309,6 +309,16 @@
 
     bool updateFrameRateOverrides(GlobalSignals, Fps displayRefreshRate) EXCLUDES(mPolicyLock);
 
+    // Returns true if the small dirty detection is enabled.
+    bool supportSmallDirtyDetection() const {
+        return mFeatures.test(Feature::kSmallDirtyContentDetection);
+    }
+
+    // Returns true if the dirty area is less than threshold.
+    bool isSmallDirtyArea(uint32_t dirtyArea) const {
+        return mLayerHistory.isSmallDirtyArea(dirtyArea);
+    }
+
 private:
     friend class TestableScheduler;
 
diff --git a/services/surfaceflinger/Scheduler/include/scheduler/Features.h b/services/surfaceflinger/Scheduler/include/scheduler/Features.h
index 200407d..7c72ac6 100644
--- a/services/surfaceflinger/Scheduler/include/scheduler/Features.h
+++ b/services/surfaceflinger/Scheduler/include/scheduler/Features.h
@@ -28,6 +28,7 @@
     kContentDetection = 1 << 2,
     kTracePredictedVsync = 1 << 3,
     kBackpressureGpuComposition = 1 << 4,
+    kSmallDirtyContentDetection = 1 << 5,
 };
 
 using FeatureFlags = ftl::Flags<Feature>;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index cb8edc3..940a4c6 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3989,6 +3989,9 @@
 
     if (sysprop::use_content_detection_for_refresh_rate(false)) {
         features |= Feature::kContentDetection;
+        if (base::GetBoolProperty("debug.sf.enable_small_dirty_detection"s, false)) {
+            features |= Feature::kSmallDirtyContentDetection;
+        }
     }
     if (base::GetBoolProperty("debug.sf.show_predicted_vsync"s, false)) {
         features |= Feature::kTracePredictedVsync;
@@ -8334,6 +8337,15 @@
 void SurfaceFlinger::onActiveDisplaySizeChanged(const DisplayDevice& activeDisplay) {
     mScheduler->onActiveDisplayAreaChanged(activeDisplay.getWidth() * activeDisplay.getHeight());
     getRenderEngine().onActiveDisplaySizeChanged(activeDisplay.getSize());
+
+    // Notify layers to update small dirty flag.
+    if (mScheduler->supportSmallDirtyDetection()) {
+        mCurrentState.traverse([&](Layer* layer) {
+            if (layer->getLayerStack() == activeDisplay.getLayerStack()) {
+                layer->setIsSmallDirty();
+            }
+        });
+    }
 }
 
 sp<DisplayDevice> SurfaceFlinger::getActivatableDisplay() const {
diff --git a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
index 51b5b05..b67494f 100644
--- a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
@@ -1070,6 +1070,77 @@
     recordFramesAndExpect(layer, time, 27.1_Hz, 30_Hz, PRESENT_TIME_HISTORY_SIZE);
 }
 
+TEST_F(LayerHistoryTest, smallDirtyLayer) {
+    auto layer = createLayer();
+
+    EXPECT_CALL(*layer, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer, getFrameRateForLayerTree()).WillRepeatedly(Return(Layer::FrameRate()));
+
+    nsecs_t time = systemTime();
+
+    EXPECT_EQ(1, layerCount());
+    EXPECT_EQ(0, activeLayerCount());
+    EXPECT_EQ(0, frequentLayerCount(time));
+
+    LayerHistory::Summary summary;
+
+    // layer is active but infrequent.
+    for (int i = 0; i < PRESENT_TIME_HISTORY_SIZE; i++) {
+        auto props = layer->getLayerProps();
+        if (i % 3 == 0) {
+            props.isSmallDirty = false;
+        } else {
+            props.isSmallDirty = true;
+        }
+
+        history().record(layer->getSequence(), props, time, time,
+                         LayerHistory::LayerUpdateType::Buffer);
+        time += HI_FPS_PERIOD;
+        summary = summarizeLayerHistory(time);
+    }
+
+    ASSERT_EQ(1, summary.size());
+    ASSERT_EQ(LayerHistory::LayerVoteType::Heuristic, summary[0].vote);
+    EXPECT_GE(HI_FPS, summary[0].desiredRefreshRate);
+}
+
+TEST_F(LayerHistoryTest, smallDirtyInMultiLayer) {
+    auto layer1 = createLayer("UI");
+    auto layer2 = createLayer("Video");
+
+    EXPECT_CALL(*layer1, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer1, getFrameRateForLayerTree()).WillRepeatedly(Return(Layer::FrameRate()));
+
+    EXPECT_CALL(*layer2, isVisible()).WillRepeatedly(Return(true));
+    EXPECT_CALL(*layer2, getFrameRateForLayerTree())
+            .WillRepeatedly(
+                    Return(Layer::FrameRate(30_Hz, Layer::FrameRateCompatibility::Default)));
+
+    nsecs_t time = systemTime();
+
+    EXPECT_EQ(2, layerCount());
+    EXPECT_EQ(0, activeLayerCount());
+    EXPECT_EQ(0, frequentLayerCount(time));
+
+    LayerHistory::Summary summary;
+
+    // layer1 is active but infrequent.
+    for (int i = 0; i < PRESENT_TIME_HISTORY_SIZE; i++) {
+        auto props = layer1->getLayerProps();
+        props.isSmallDirty = true;
+        history().record(layer1->getSequence(), props, 0 /*presentTime*/, time,
+                         LayerHistory::LayerUpdateType::Buffer);
+        history().record(layer2->getSequence(), layer2->getLayerProps(), time, time,
+                         LayerHistory::LayerUpdateType::Buffer);
+        time += HI_FPS_PERIOD;
+        summary = summarizeLayerHistory(time);
+    }
+
+    ASSERT_EQ(1, summary.size());
+    ASSERT_EQ(LayerHistory::LayerVoteType::ExplicitDefault, summary[0].vote);
+    ASSERT_EQ(30_Hz, summary[0].desiredRefreshRate);
+}
+
 class LayerHistoryTestParameterized : public LayerHistoryTest,
                                       public testing::WithParamInterface<std::chrono::nanoseconds> {
 };