diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 5922f3a..83bc069 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -353,6 +353,8 @@
         mTransactionNestCount(other.mTransactionNestCount),
         mAnimation(other.mAnimation),
         mEarlyWakeup(other.mEarlyWakeup),
+        mExplicitEarlyWakeupStart(other.mExplicitEarlyWakeupStart),
+        mExplicitEarlyWakeupEnd(other.mExplicitEarlyWakeupEnd),
         mContainsBuffer(other.mContainsBuffer),
         mDesiredPresentTime(other.mDesiredPresentTime) {
     mDisplayStates = other.mDisplayStates;
@@ -375,6 +377,8 @@
     const uint32_t transactionNestCount = parcel->readUint32();
     const bool animation = parcel->readBool();
     const bool earlyWakeup = parcel->readBool();
+    const bool explicitEarlyWakeupStart = parcel->readBool();
+    const bool explicitEarlyWakeupEnd = parcel->readBool();
     const bool containsBuffer = parcel->readBool();
     const int64_t desiredPresentTime = parcel->readInt64();
 
@@ -443,6 +447,8 @@
     mTransactionNestCount = transactionNestCount;
     mAnimation = animation;
     mEarlyWakeup = earlyWakeup;
+    mExplicitEarlyWakeupStart = explicitEarlyWakeupStart;
+    mExplicitEarlyWakeupEnd = explicitEarlyWakeupEnd;
     mContainsBuffer = containsBuffer;
     mDesiredPresentTime = desiredPresentTime;
     mDisplayStates = displayStates;
@@ -470,6 +476,8 @@
     parcel->writeUint32(mTransactionNestCount);
     parcel->writeBool(mAnimation);
     parcel->writeBool(mEarlyWakeup);
+    parcel->writeBool(mExplicitEarlyWakeupStart);
+    parcel->writeBool(mExplicitEarlyWakeupEnd);
     parcel->writeBool(mContainsBuffer);
     parcel->writeInt64(mDesiredPresentTime);
     parcel->writeUint32(static_cast<uint32_t>(mDisplayStates.size()));
@@ -545,6 +553,8 @@
 
     mContainsBuffer |= other.mContainsBuffer;
     mEarlyWakeup = mEarlyWakeup || other.mEarlyWakeup;
+    mExplicitEarlyWakeupStart = mExplicitEarlyWakeupStart || other.mExplicitEarlyWakeupStart;
+    mExplicitEarlyWakeupEnd = mExplicitEarlyWakeupEnd || other.mExplicitEarlyWakeupEnd;
     other.clear();
     return *this;
 }
@@ -559,6 +569,8 @@
     mTransactionNestCount = 0;
     mAnimation = false;
     mEarlyWakeup = false;
+    mExplicitEarlyWakeupStart = false;
+    mExplicitEarlyWakeupEnd = false;
     mDesiredPresentTime = -1;
 }
 
@@ -682,9 +694,20 @@
         flags |= ISurfaceComposer::eEarlyWakeup;
     }
 
+    // If both mExplicitEarlyWakeupStart and mExplicitEarlyWakeupEnd are set
+    // it is equivalent for none
+    if (mExplicitEarlyWakeupStart && !mExplicitEarlyWakeupEnd) {
+        flags |= ISurfaceComposer::eExplicitEarlyWakeupStart;
+    }
+    if (mExplicitEarlyWakeupEnd && !mExplicitEarlyWakeupStart) {
+        flags |= ISurfaceComposer::eExplicitEarlyWakeupEnd;
+    }
+
     mForceSynchronous = false;
     mAnimation = false;
     mEarlyWakeup = false;
+    mExplicitEarlyWakeupStart = false;
+    mExplicitEarlyWakeupEnd = false;
 
     sp<IBinder> applyToken = IInterface::asBinder(TransactionCompletedListener::getIInstance());
     sf->setTransactionState(composerStates, displayStates, flags, applyToken, mInputWindowCommands,
@@ -731,6 +754,14 @@
     mEarlyWakeup = true;
 }
 
+void SurfaceComposerClient::Transaction::setExplicitEarlyWakeupStart() {
+    mExplicitEarlyWakeupStart = true;
+}
+
+void SurfaceComposerClient::Transaction::setExplicitEarlyWakeupEnd() {
+    mExplicitEarlyWakeupEnd = true;
+}
+
 layer_state_t* SurfaceComposerClient::Transaction::getLayerState(const sp<IBinder>& handle) {
     if (mComposerStates.count(handle) == 0) {
         // we don't have it, add an initialized layer_state to our list
diff --git a/libs/gui/include/gui/ISurfaceComposer.h b/libs/gui/include/gui/ISurfaceComposer.h
index b49fa1b..8d3160a 100644
--- a/libs/gui/include/gui/ISurfaceComposer.h
+++ b/libs/gui/include/gui/ISurfaceComposer.h
@@ -81,12 +81,20 @@
     // flags for setTransactionState()
     enum {
         eSynchronous = 0x01,
-        eAnimation   = 0x02,
+        eAnimation = 0x02,
 
-        // Indicates that this transaction will likely result in a lot of layers being composed, and
-        // thus, SurfaceFlinger should wake-up earlier to avoid missing frame deadlines. In this
-        // case SurfaceFlinger will wake up at (sf vsync offset - debug.sf.early_phase_offset_ns)
-        eEarlyWakeup = 0x04
+        // DEPRECATED - use eExplicitEarlyWakeup[Start|End]
+        eEarlyWakeup = 0x04,
+
+        // Explicit indication that this transaction and others to follow will likely result in a
+        // lot of layers being composed, and thus, SurfaceFlinger should wake-up earlier to avoid
+        // missing frame deadlines. In this case SurfaceFlinger will wake up at
+        // (sf vsync offset - debug.sf.early_phase_offset_ns). SurfaceFlinger will continue to be
+        // in the early configuration until it receives eExplicitEarlyWakeupEnd. These flags are
+        // expected to be used by WindowManager only and are guarded by
+        // android.permission.ACCESS_SURFACE_FLINGER
+        eExplicitEarlyWakeupStart = 0x08,
+        eExplicitEarlyWakeupEnd = 0x10,
     };
 
     enum VsyncSource {
diff --git a/libs/gui/include/gui/SurfaceComposerClient.h b/libs/gui/include/gui/SurfaceComposerClient.h
index e981a39..adcb898 100644
--- a/libs/gui/include/gui/SurfaceComposerClient.h
+++ b/libs/gui/include/gui/SurfaceComposerClient.h
@@ -345,10 +345,12 @@
         std::unordered_map<sp<ITransactionCompletedListener>, CallbackInfo, TCLHash>
                 mListenerCallbacks;
 
-        uint32_t                    mForceSynchronous = 0;
-        uint32_t                    mTransactionNestCount = 0;
-        bool                        mAnimation = false;
-        bool                        mEarlyWakeup = false;
+        uint32_t mForceSynchronous = 0;
+        uint32_t mTransactionNestCount = 0;
+        bool mAnimation = false;
+        bool mEarlyWakeup = false;
+        bool mExplicitEarlyWakeupStart = false;
+        bool mExplicitEarlyWakeupEnd = false;
 
         // Indicates that the Transaction contains a buffer that should be cached
         bool mContainsBuffer = false;
@@ -547,6 +549,8 @@
         void setDisplaySize(const sp<IBinder>& token, uint32_t width, uint32_t height);
         void setAnimationTransaction();
         void setEarlyWakeup();
+        void setExplicitEarlyWakeupStart();
+        void setExplicitEarlyWakeupEnd();
     };
 
     status_t clearLayerFrameStats(const sp<IBinder>& token) const;
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 9e24f909..730ea8f 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -55,13 +55,24 @@
     virtual void kernelTimerChanged(bool expired) = 0;
 };
 
-class Scheduler {
+class IPhaseOffsetControl {
+public:
+    virtual ~IPhaseOffsetControl() = default;
+    virtual void setPhaseOffset(scheduler::ConnectionHandle, nsecs_t phaseOffset) = 0;
+};
+
+class Scheduler : public IPhaseOffsetControl {
 public:
     using RefreshRate = scheduler::RefreshRateConfigs::RefreshRate;
     using ConfigEvent = scheduler::RefreshRateConfigEvent;
 
     // Indicates whether to start the transaction early, or at vsync time.
-    enum class TransactionStart { EARLY, NORMAL };
+    enum class TransactionStart {
+        Early,      // DEPRECATED. Start the transaction early. Times out on its own
+        EarlyStart, // Start the transaction early and keep this config until EarlyEnd
+        EarlyEnd,   // End the early config started at EarlyStart
+        Normal      // Start the transaction at the normal time
+    };
 
     Scheduler(impl::EventControlThread::SetVSyncEnabledFunction,
               const scheduler::RefreshRateConfigs&, ISchedulerCallback& schedulerCallback,
@@ -90,7 +101,7 @@
     void onScreenReleased(ConnectionHandle);
 
     // Modifies phase offset in the event thread.
-    void setPhaseOffset(ConnectionHandle, nsecs_t phaseOffset);
+    void setPhaseOffset(ConnectionHandle, nsecs_t phaseOffset) override;
 
     void getDisplayStatInfo(DisplayStatInfo* stats);
 
diff --git a/services/surfaceflinger/Scheduler/VSyncModulator.cpp b/services/surfaceflinger/Scheduler/VSyncModulator.cpp
index 510dc2d..2567c04 100644
--- a/services/surfaceflinger/Scheduler/VSyncModulator.cpp
+++ b/services/surfaceflinger/Scheduler/VSyncModulator.cpp
@@ -31,11 +31,11 @@
 
 namespace android::scheduler {
 
-VSyncModulator::VSyncModulator(Scheduler& scheduler,
+VSyncModulator::VSyncModulator(IPhaseOffsetControl& phaseOffsetControl,
                                Scheduler::ConnectionHandle appConnectionHandle,
                                Scheduler::ConnectionHandle sfConnectionHandle,
                                const OffsetsConfig& config)
-      : mScheduler(scheduler),
+      : mPhaseOffsetControl(phaseOffsetControl),
         mAppConnectionHandle(appConnectionHandle),
         mSfConnectionHandle(sfConnectionHandle),
         mOffsetsConfig(config) {
@@ -51,14 +51,35 @@
 }
 
 void VSyncModulator::setTransactionStart(Scheduler::TransactionStart transactionStart) {
-    if (transactionStart == Scheduler::TransactionStart::EARLY) {
+    switch (transactionStart) {
+        case Scheduler::TransactionStart::EarlyStart:
+            ALOGW_IF(mExplicitEarlyWakeup, "Already in TransactionStart::EarlyStart");
+            mExplicitEarlyWakeup = true;
+            break;
+        case Scheduler::TransactionStart::EarlyEnd:
+            ALOGW_IF(!mExplicitEarlyWakeup, "Not in TransactionStart::EarlyStart");
+            mExplicitEarlyWakeup = false;
+            break;
+        case Scheduler::TransactionStart::Normal:
+        case Scheduler::TransactionStart::Early:
+            // Non explicit don't change the explicit early wakeup state
+            break;
+    }
+
+    if (mTraceDetailedInfo) {
+        ATRACE_INT("mExplicitEarlyWakeup", mExplicitEarlyWakeup);
+    }
+
+    if (!mExplicitEarlyWakeup &&
+        (transactionStart == Scheduler::TransactionStart::Early ||
+         transactionStart == Scheduler::TransactionStart::EarlyEnd)) {
         mRemainingEarlyFrameCount = MIN_EARLY_FRAME_COUNT_TRANSACTION;
         mEarlyTxnStartTime = std::chrono::steady_clock::now();
     }
 
     // An early transaction stays an early transaction.
     if (transactionStart == mTransactionStart ||
-        mTransactionStart == Scheduler::TransactionStart::EARLY) {
+        mTransactionStart == Scheduler::TransactionStart::EarlyEnd) {
         return;
     }
     mTransactionStart = transactionStart;
@@ -67,8 +88,8 @@
 
 void VSyncModulator::onTransactionHandled() {
     mTxnAppliedTime = std::chrono::steady_clock::now();
-    if (mTransactionStart == Scheduler::TransactionStart::NORMAL) return;
-    mTransactionStart = Scheduler::TransactionStart::NORMAL;
+    if (mTransactionStart == Scheduler::TransactionStart::Normal) return;
+    mTransactionStart = Scheduler::TransactionStart::Normal;
     updateOffsets();
 }
 
@@ -91,11 +112,10 @@
 void VSyncModulator::onRefreshed(bool usedRenderEngine) {
     bool updateOffsetsNeeded = false;
 
-    // Apply a 1ms margin to account for potential data races
+    // Apply a margin to account for potential data races
     // This might make us stay in early offsets for one
     // additional frame but it's better to be conservative here.
-    static const constexpr std::chrono::nanoseconds kMargin = 1ms;
-    if ((mEarlyTxnStartTime.load() + kMargin) < mTxnAppliedTime.load()) {
+    if ((mEarlyTxnStartTime.load() + MARGIN_FOR_TX_APPLY) < mTxnAppliedTime.load()) {
         if (mRemainingEarlyFrameCount > 0) {
             mRemainingEarlyFrameCount--;
             updateOffsetsNeeded = true;
@@ -121,8 +141,8 @@
 const VSyncModulator::Offsets& VSyncModulator::getNextOffsets() const {
     // Early offsets are used if we're in the middle of a refresh rate
     // change, or if we recently begin a transaction.
-    if (mTransactionStart == Scheduler::TransactionStart::EARLY || mRemainingEarlyFrameCount > 0 ||
-        mRefreshRateChangePending) {
+    if (mExplicitEarlyWakeup || mTransactionStart == Scheduler::TransactionStart::EarlyEnd ||
+        mRemainingEarlyFrameCount > 0 || mRefreshRateChangePending) {
         return mOffsetsConfig.early;
     } else if (mRemainingRenderEngineUsageCount > 0) {
         return mOffsetsConfig.earlyGl;
@@ -139,8 +159,8 @@
 void VSyncModulator::updateOffsetsLocked() {
     const Offsets& offsets = getNextOffsets();
 
-    mScheduler.setPhaseOffset(mSfConnectionHandle, offsets.sf);
-    mScheduler.setPhaseOffset(mAppConnectionHandle, offsets.app);
+    mPhaseOffsetControl.setPhaseOffset(mSfConnectionHandle, offsets.sf);
+    mPhaseOffsetControl.setPhaseOffset(mAppConnectionHandle, offsets.app);
 
     mOffsets = offsets;
 
diff --git a/services/surfaceflinger/Scheduler/VSyncModulator.h b/services/surfaceflinger/Scheduler/VSyncModulator.h
index d777ef9..ab678c9 100644
--- a/services/surfaceflinger/Scheduler/VSyncModulator.h
+++ b/services/surfaceflinger/Scheduler/VSyncModulator.h
@@ -38,6 +38,9 @@
     // switch in and out of gl composition.
     static constexpr int MIN_EARLY_GL_FRAME_COUNT_TRANSACTION = 2;
 
+    // Margin used to account for potential data races
+    static const constexpr std::chrono::nanoseconds MARGIN_FOR_TX_APPLY = 1ms;
+
 public:
     // Wrapper for a collection of surfaceflinger/app offsets for a particular
     // configuration.
@@ -62,7 +65,7 @@
         bool operator!=(const OffsetsConfig& other) const { return !(*this == other); }
     };
 
-    VSyncModulator(Scheduler&, ConnectionHandle appConnectionHandle,
+    VSyncModulator(IPhaseOffsetControl&, ConnectionHandle appConnectionHandle,
                    ConnectionHandle sfConnectionHandle, const OffsetsConfig&);
 
     void setPhaseOffsets(const OffsetsConfig&) EXCLUDES(mMutex);
@@ -91,13 +94,14 @@
     Offsets getOffsets() const EXCLUDES(mMutex);
 
 private:
+    friend class VSyncModulatorTest;
     // Returns the next offsets that we should be using
     const Offsets& getNextOffsets() const REQUIRES(mMutex);
     // Updates offsets and persists them into the scheduler framework.
     void updateOffsets() EXCLUDES(mMutex);
     void updateOffsetsLocked() REQUIRES(mMutex);
 
-    Scheduler& mScheduler;
+    IPhaseOffsetControl& mPhaseOffsetControl;
     const ConnectionHandle mAppConnectionHandle;
     const ConnectionHandle mSfConnectionHandle;
 
@@ -107,8 +111,9 @@
     Offsets mOffsets GUARDED_BY(mMutex){mOffsetsConfig.late};
 
     std::atomic<Scheduler::TransactionStart> mTransactionStart =
-            Scheduler::TransactionStart::NORMAL;
+            Scheduler::TransactionStart::Normal;
     std::atomic<bool> mRefreshRateChangePending = false;
+    std::atomic<bool> mExplicitEarlyWakeup = false;
     std::atomic<int> mRemainingEarlyFrameCount = 0;
     std::atomic<int> mRemainingRenderEngineUsageCount = 0;
     std::atomic<std::chrono::steady_clock::time_point> mEarlyTxnStartTime = {};
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 068049d..ef315e2 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3236,7 +3236,7 @@
 }
 
 uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags) {
-    return setTransactionFlags(flags, Scheduler::TransactionStart::NORMAL);
+    return setTransactionFlags(flags, Scheduler::TransactionStart::Normal);
 }
 
 uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags,
@@ -3453,15 +3453,36 @@
         mForceTraversal = true;
     }
 
+    const auto transactionStart = [](uint32_t flags) {
+        if (flags & eEarlyWakeup) {
+            return Scheduler::TransactionStart::Early;
+        }
+        if (flags & eExplicitEarlyWakeupEnd) {
+            return Scheduler::TransactionStart::EarlyEnd;
+        }
+        if (flags & eExplicitEarlyWakeupStart) {
+            return Scheduler::TransactionStart::EarlyStart;
+        }
+        return Scheduler::TransactionStart::Normal;
+    }(flags);
+
     if (transactionFlags) {
         if (mInterceptor->isEnabled()) {
             mInterceptor->saveTransaction(states, mCurrentState.displays, displays, flags);
         }
 
+        // TODO(b/159125966): Remove eEarlyWakeup completly as no client should use this flag
+        if (flags & eEarlyWakeup) {
+            ALOGW("eEarlyWakeup is deprecated. Use eExplicitEarlyWakeup[Start|End]");
+        }
+
+        if (!privileged && (flags & (eExplicitEarlyWakeupStart | eExplicitEarlyWakeupEnd))) {
+            ALOGE("Only WindowManager is allowed to use eExplicitEarlyWakeup[Start|End] flags");
+            flags &= ~(eExplicitEarlyWakeupStart | eExplicitEarlyWakeupEnd);
+        }
+
         // this triggers the transaction
-        const auto start = (flags & eEarlyWakeup) ? Scheduler::TransactionStart::EARLY
-                                                  : Scheduler::TransactionStart::NORMAL;
-        setTransactionFlags(transactionFlags, start);
+        setTransactionFlags(transactionFlags, transactionStart);
 
         if (flags & eAnimation) {
             mAnimTransactionPending = true;
@@ -3498,6 +3519,13 @@
                 break;
             }
         }
+    } else {
+        // even if a transaction is not needed, we need to update VsyncModulator
+        // about explicit early indications
+        if (transactionStart == Scheduler::TransactionStart::EarlyStart ||
+            transactionStart == Scheduler::TransactionStart::EarlyEnd) {
+            mVSyncModulator->setTransactionStart(transactionStart);
+        }
     }
 }
 
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 7574ff1..3c4a791 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -62,6 +62,7 @@
         "StrongTypingTest.cpp",
         "VSyncDispatchTimerQueueTest.cpp",
         "VSyncDispatchRealtimeTest.cpp",
+        "VSyncModulatorTest.cpp",
         "VSyncPredictorTest.cpp",
         "VSyncReactorTest.cpp",
         "mock/DisplayHardware/MockComposer.cpp",
diff --git a/services/surfaceflinger/tests/unittests/VSyncModulatorTest.cpp b/services/surfaceflinger/tests/unittests/VSyncModulatorTest.cpp
new file mode 100644
index 0000000..9c1ec07
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/VSyncModulatorTest.cpp
@@ -0,0 +1,301 @@
+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LibSurfaceFlingerUnittests"
+#define LOG_NDEBUG 0
+
+#include "Scheduler/VSyncModulator.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+using namespace testing;
+
+namespace android::scheduler {
+
+class MockScheduler : public IPhaseOffsetControl {
+public:
+    void setPhaseOffset(ConnectionHandle handle, nsecs_t phaseOffset) {
+        mPhaseOffset[handle] = phaseOffset;
+    }
+
+    nsecs_t getOffset(ConnectionHandle handle) { return mPhaseOffset[handle]; }
+
+private:
+    std::unordered_map<ConnectionHandle, nsecs_t> mPhaseOffset;
+};
+
+class VSyncModulatorTest : public testing::Test {
+protected:
+    static constexpr auto MIN_EARLY_FRAME_COUNT_TRANSACTION =
+            VSyncModulator::MIN_EARLY_FRAME_COUNT_TRANSACTION;
+    // Add a 1ms slack to avoid strange timer race conditions.
+    static constexpr auto MARGIN_FOR_TX_APPLY = VSyncModulator::MARGIN_FOR_TX_APPLY + 1ms;
+
+    // Used to enumerate the different offsets we have
+    enum {
+        SF_LATE,
+        APP_LATE,
+        SF_EARLY,
+        APP_EARLY,
+        SF_EARLY_GL,
+        APP_EARLY_GL,
+    };
+
+    std::unique_ptr<VSyncModulator> mVSyncModulator;
+    MockScheduler mMockScheduler;
+    ConnectionHandle mAppConnection{1};
+    ConnectionHandle mSfConnection{2};
+    VSyncModulator::OffsetsConfig mOffsets = {{SF_EARLY, APP_EARLY},
+                                              {SF_EARLY_GL, APP_EARLY_GL},
+                                              {SF_LATE, APP_LATE}};
+
+    void SetUp() override {
+        mVSyncModulator = std::make_unique<VSyncModulator>(mMockScheduler, mAppConnection,
+                                                           mSfConnection, mOffsets);
+        mVSyncModulator->setPhaseOffsets(mOffsets);
+
+        EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+    };
+
+    void TearDown() override { mVSyncModulator.reset(); }
+};
+
+TEST_F(VSyncModulatorTest, Normal) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::Normal);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+    }
+}
+
+TEST_F(VSyncModulatorTest, EarlyEnd) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+TEST_F(VSyncModulatorTest, EarlyStart) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyStart);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+TEST_F(VSyncModulatorTest, EarlyStartWithEarly) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyStart);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::Early);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+TEST_F(VSyncModulatorTest, EarlyStartWithMoreTransactions) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyStart);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::Normal);
+        std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+TEST_F(VSyncModulatorTest, EarlyStartAfterEarlyEnd) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyStart);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+TEST_F(VSyncModulatorTest, EarlyStartAfterEarlyEndWithMoreTransactions) {
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyStart);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < 5 * MIN_EARLY_FRAME_COUNT_TRANSACTION; i++) {
+        mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::Normal);
+        std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->setTransactionStart(Scheduler::TransactionStart::EarlyEnd);
+    std::this_thread::sleep_for(MARGIN_FOR_TX_APPLY);
+    mVSyncModulator->onTransactionHandled();
+    EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+
+    for (int i = 0; i < MIN_EARLY_FRAME_COUNT_TRANSACTION - 1; i++) {
+        mVSyncModulator->onRefreshed(false);
+        EXPECT_EQ(APP_EARLY, mMockScheduler.getOffset(mAppConnection));
+        EXPECT_EQ(SF_EARLY, mMockScheduler.getOffset(mSfConnection));
+    }
+
+    mVSyncModulator->onRefreshed(false);
+    EXPECT_EQ(APP_LATE, mMockScheduler.getOffset(mAppConnection));
+    EXPECT_EQ(SF_LATE, mMockScheduler.getOffset(mSfConnection));
+}
+
+} // namespace android::scheduler