Merge "SF: tune infrequent layers for animations"
diff --git a/services/surfaceflinger/Scheduler/LayerInfo.cpp b/services/surfaceflinger/Scheduler/LayerInfo.cpp
index f9c9023..0142ccd 100644
--- a/services/surfaceflinger/Scheduler/LayerInfo.cpp
+++ b/services/surfaceflinger/Scheduler/LayerInfo.cpp
@@ -77,12 +77,43 @@
 
 bool LayerInfo::isFrequent(nsecs_t now) const {
     using fps_approx_ops::operator>=;
-    // If we know nothing about this layer we consider it as frequent as it might be the start
-    // of an animation.
+    // If we know nothing about this layer (e.g. after touch event),
+    // we consider it as frequent as it might be the start of an animation.
     if (mFrameTimes.size() < kFrequentLayerWindowSize) {
         return true;
     }
-    return getFps(now) >= kMinFpsForFrequentLayer;
+
+    // Non-active layers are also infrequent
+    if (mLastUpdatedTime < getActiveLayerThreshold(now)) {
+        return false;
+    }
+
+    // We check whether we can classify this layer as frequent or infrequent:
+    //  - frequent: a layer posted kFrequentLayerWindowSize within
+    //              kMaxPeriodForFrequentLayerNs of each other.
+    // -  infrequent: a layer posted kFrequentLayerWindowSize with longer
+    //                gaps than kFrequentLayerWindowSize.
+    // If we can't determine the layer classification yet, we return the last
+    // classification.
+    bool isFrequent = true;
+    bool isInfrequent = true;
+    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;
+        } else {
+            isFrequent = false;
+        }
+    }
+
+    if (isFrequent || isInfrequent) {
+        return isFrequent;
+    }
+
+    // If we can't determine whether the layer is frequent or not, we return
+    // the last known classification.
+    return !mLastRefreshRate.infrequent;
 }
 
 Fps LayerInfo::getFps(nsecs_t now) const {
@@ -235,14 +266,14 @@
     if (isAnimating(now)) {
         ATRACE_FORMAT_INSTANT("animating");
         ALOGV("%s is animating", mName.c_str());
-        mLastRefreshRate.animatingOrInfrequent = true;
+        mLastRefreshRate.animating = true;
         return {LayerHistory::LayerVoteType::Max, Fps()};
     }
 
     if (!isFrequent(now)) {
         ATRACE_FORMAT_INSTANT("infrequent");
         ALOGV("%s is infrequent", mName.c_str());
-        mLastRefreshRate.animatingOrInfrequent = true;
+        mLastRefreshRate.infrequent = true;
         // Infrequent layers vote for mininal refresh rate for
         // battery saving purposes and also to prevent b/135718869.
         return {LayerHistory::LayerVoteType::Min, Fps()};
@@ -251,7 +282,7 @@
     // If the layer was previously tagged as animating or infrequent, we clear
     // the history as it is likely the layer just changed its behavior
     // and we should not look at stale data
-    if (mLastRefreshRate.animatingOrInfrequent) {
+    if (mLastRefreshRate.animating || mLastRefreshRate.infrequent) {
         clearHistory(now);
     }
 
diff --git a/services/surfaceflinger/Scheduler/LayerInfo.h b/services/surfaceflinger/Scheduler/LayerInfo.h
index a5ffbbe..93485be 100644
--- a/services/surfaceflinger/Scheduler/LayerInfo.h
+++ b/services/surfaceflinger/Scheduler/LayerInfo.h
@@ -53,7 +53,7 @@
     // Layer is considered frequent if the earliest value in the window of most recent present times
     // is within a threshold. If a layer is infrequent, its average refresh rate is disregarded in
     // favor of a low refresh rate.
-    static constexpr size_t kFrequentLayerWindowSize = 3;
+    static constexpr size_t kFrequentLayerWindowSize = 4;
     static constexpr Fps kMinFpsForFrequentLayer = 10_Hz;
     static constexpr auto kMaxPeriodForFrequentLayerNs =
             std::chrono::nanoseconds(kMinFpsForFrequentLayer.getPeriodNsecs()) + 1ms;
@@ -214,7 +214,10 @@
         Fps reported;
         // Whether the last reported rate for LayerInfo::getRefreshRate()
         // was due to animation or infrequent updates
-        bool animatingOrInfrequent = false;
+        bool animating = false;
+        // Whether the last reported rate for LayerInfo::getRefreshRate()
+        // was due to infrequent updates
+        bool infrequent = false;
     };
 
     // Class to store past calculated refresh rate and determine whether
diff --git a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
index 979924a..8397f8d 100644
--- a/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerHistoryTest.cpp
@@ -51,8 +51,6 @@
     static constexpr auto MAX_FREQUENT_LAYER_PERIOD_NS = LayerInfo::kMaxPeriodForFrequentLayerNs;
     static constexpr auto FREQUENT_LAYER_WINDOW_SIZE = LayerInfo::kFrequentLayerWindowSize;
     static constexpr auto PRESENT_TIME_HISTORY_DURATION = LayerInfo::HISTORY_DURATION;
-    static constexpr auto REFRESH_RATE_AVERAGE_HISTORY_DURATION =
-            LayerInfo::RefreshRateHistory::HISTORY_DURATION;
 
     static constexpr Fps LO_FPS = 30_Hz;
     static constexpr auto LO_FPS_PERIOD = LO_FPS.getPeriodNsecs();
@@ -607,7 +605,7 @@
     // advance the time for the previous frame to be inactive
     time += MAX_ACTIVE_LAYER_PERIOD_NS.count();
 
-    // Now event if we post a quick few frame we should stay infrequent
+    // Now even if we post a quick few frame we should stay infrequent
     for (int i = 0; i < FREQUENT_LAYER_WINDOW_SIZE - 1; i++) {
         history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
         time += HI_FPS_PERIOD;
@@ -706,6 +704,88 @@
     EXPECT_EQ(1, animatingLayerCount(time));
 }
 
+TEST_F(LayerHistoryTest, frequentLayerBecomingInfrequentAndBack) {
+    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));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // Fill up the window with frequent updates
+    for (int i = 0; i < FREQUENT_LAYER_WINDOW_SIZE; i++) {
+        history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+        time += (60_Hz).getPeriodNsecs();
+
+        EXPECT_EQ(1, layerCount());
+        ASSERT_EQ(1, summarizeLayerHistory(time).size());
+        EXPECT_EQ(LayerHistory::LayerVoteType::Max, summarizeLayerHistory(time)[0].vote);
+        EXPECT_EQ(1, activeLayerCount());
+        EXPECT_EQ(1, frequentLayerCount(time));
+    }
+
+    // posting a buffer after long inactivity should retain the layer as active
+    time += std::chrono::nanoseconds(3s).count();
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Heuristic, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(60_Hz, summarizeLayerHistory(time)[0].desiredRefreshRate);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(1, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // posting more infrequent buffer should make the layer infrequent
+    time += (MAX_FREQUENT_LAYER_PERIOD_NS + 1ms).count();
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    time += (MAX_FREQUENT_LAYER_PERIOD_NS + 1ms).count();
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Min, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(0, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // posting another buffer should keep the layer infrequent
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Min, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(0, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // posting more buffers would mean starting of an animation, so making the layer frequent
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Max, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(1, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // posting a buffer after long inactivity should retain the layer as active
+    time += std::chrono::nanoseconds(3s).count();
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Max, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(1, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+
+    // posting another buffer should keep the layer frequent
+    time += (60_Hz).getPeriodNsecs();
+    history().record(layer.get(), time, time, LayerHistory::LayerUpdateType::Buffer);
+    ASSERT_EQ(1, summarizeLayerHistory(time).size());
+    EXPECT_EQ(LayerHistory::LayerVoteType::Max, summarizeLayerHistory(time)[0].vote);
+    EXPECT_EQ(1, activeLayerCount());
+    EXPECT_EQ(1, frequentLayerCount(time));
+    EXPECT_EQ(0, animatingLayerCount(time));
+}
+
 TEST_F(LayerHistoryTest, getFramerate) {
     auto layer = createLayer();