Merge "SF: Remove ConnectionHandle concept in Scheduler" into main
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 6979f03..e6c58a3 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -60,14 +60,6 @@
 #include "VsyncController.h"
 #include "VsyncSchedule.h"
 
-#define RETURN_IF_INVALID_HANDLE(handle, ...)                        \
-    do {                                                             \
-        if (mConnections.count(handle) == 0) {                       \
-            ALOGE("Invalid connection handle %" PRIuPTR, handle.id); \
-            return __VA_ARGS__;                                      \
-        }                                                            \
-    } while (false)
-
 namespace android::scheduler {
 
 Scheduler::Scheduler(ICompositor& compositor, ISchedulerCallback& callback, FeatureFlags features,
@@ -344,40 +336,26 @@
     }
 }
 
-ConnectionHandle Scheduler::createEventThread(Cycle cycle,
-                                              frametimeline::TokenManager* tokenManager,
-                                              std::chrono::nanoseconds workDuration,
-                                              std::chrono::nanoseconds readyDuration) {
+void Scheduler::createEventThread(Cycle cycle, frametimeline::TokenManager* tokenManager,
+                                  std::chrono::nanoseconds workDuration,
+                                  std::chrono::nanoseconds readyDuration) {
     auto eventThread =
             std::make_unique<android::impl::EventThread>(cycle == Cycle::Render ? "app" : "appSf",
                                                          getVsyncSchedule(), tokenManager, *this,
                                                          workDuration, readyDuration);
 
-    auto& handle = cycle == Cycle::Render ? mAppConnectionHandle : mSfConnectionHandle;
-    handle = createConnection(std::move(eventThread));
-    return handle;
-}
-
-ConnectionHandle Scheduler::createConnection(std::unique_ptr<EventThread> eventThread) {
-    const ConnectionHandle handle = ConnectionHandle{mNextConnectionHandleId++};
-    ALOGV("Creating a connection handle with ID %" PRIuPTR, handle.id);
-
-    auto connection = eventThread->createEventConnection();
-
-    std::lock_guard<std::mutex> lock(mConnectionsLock);
-    mConnections.emplace(handle, Connection{connection, std::move(eventThread)});
-    return handle;
+    if (cycle == Cycle::Render) {
+        mRenderEventThread = std::move(eventThread);
+        mRenderEventConnection = mRenderEventThread->createEventConnection();
+    } else {
+        mLastCompositeEventThread = std::move(eventThread);
+        mLastCompositeEventConnection = mLastCompositeEventThread->createEventConnection();
+    }
 }
 
 sp<IDisplayEventConnection> Scheduler::createDisplayEventConnection(
-        ConnectionHandle handle, EventRegistrationFlags eventRegistration,
-        const sp<IBinder>& layerHandle) {
-    const auto connection = [&]() -> sp<EventThreadConnection> {
-        std::scoped_lock lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle, nullptr);
-
-        return mConnections[handle].thread->createEventConnection(eventRegistration);
-    }();
+        Cycle cycle, EventRegistrationFlags eventRegistration, const sp<IBinder>& layerHandle) {
+    const auto connection = eventThreadFor(cycle).createEventConnection(eventRegistration);
     const auto layerId = static_cast<int32_t>(LayerHandle::getLayerId(layerHandle));
 
     if (layerId != static_cast<int32_t>(UNASSIGNED_LAYER_ID)) {
@@ -397,85 +375,48 @@
     return connection;
 }
 
-sp<EventThreadConnection> Scheduler::getEventConnection(ConnectionHandle handle) {
-    std::lock_guard<std::mutex> lock(mConnectionsLock);
-    RETURN_IF_INVALID_HANDLE(handle, nullptr);
-    return mConnections[handle].connection;
+void Scheduler::onHotplugReceived(Cycle cycle, PhysicalDisplayId displayId, bool connected) {
+    if (hasEventThreads()) {
+        eventThreadFor(cycle).onHotplugReceived(displayId, connected);
+    }
 }
 
-void Scheduler::onHotplugReceived(ConnectionHandle handle, PhysicalDisplayId displayId,
-                                  bool connected) {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
+void Scheduler::onHotplugConnectionError(Cycle cycle, int32_t errorCode) {
+    if (hasEventThreads()) {
+        eventThreadFor(cycle).onHotplugConnectionError(errorCode);
     }
-
-    thread->onHotplugReceived(displayId, connected);
-}
-
-void Scheduler::onHotplugConnectionError(ConnectionHandle handle, int32_t errorCode) {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
-    }
-
-    thread->onHotplugConnectionError(errorCode);
 }
 
 void Scheduler::enableSyntheticVsync(bool enable) {
-    // TODO(b/241285945): Remove connection handles.
-    const ConnectionHandle handle = mAppConnectionHandle;
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
-    }
-    thread->enableSyntheticVsync(enable);
+    eventThreadFor(Cycle::Render).enableSyntheticVsync(enable);
 }
 
-void Scheduler::onFrameRateOverridesChanged(ConnectionHandle handle, PhysicalDisplayId displayId) {
+void Scheduler::onFrameRateOverridesChanged(Cycle cycle, PhysicalDisplayId displayId) {
     const bool supportsFrameRateOverrideByContent =
             pacesetterSelectorPtr()->supportsAppFrameRateOverrideByContent();
 
     std::vector<FrameRateOverride> overrides =
             mFrameRateOverrideMappings.getAllFrameRateOverrides(supportsFrameRateOverrideByContent);
 
-    android::EventThread* thread;
-    {
-        std::lock_guard lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
-    }
-    thread->onFrameRateOverridesChanged(displayId, std::move(overrides));
+    eventThreadFor(cycle).onFrameRateOverridesChanged(displayId, std::move(overrides));
 }
 
-void Scheduler::onHdcpLevelsChanged(ConnectionHandle handle, PhysicalDisplayId displayId,
+void Scheduler::onHdcpLevelsChanged(Cycle cycle, PhysicalDisplayId displayId,
                                     int32_t connectedLevel, int32_t maxLevel) {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
-    }
-    thread->onHdcpLevelsChanged(displayId, connectedLevel, maxLevel);
+    eventThreadFor(cycle).onHdcpLevelsChanged(displayId, connectedLevel, maxLevel);
 }
 
-void Scheduler::onPrimaryDisplayModeChanged(ConnectionHandle handle, const FrameRateMode& mode) {
+void Scheduler::onPrimaryDisplayModeChanged(Cycle cycle, const FrameRateMode& mode) {
     {
         std::lock_guard<std::mutex> lock(mPolicyLock);
         // Cache the last reported modes for primary display.
-        mPolicy.cachedModeChangedParams = {handle, mode};
+        mPolicy.cachedModeChangedParams = {cycle, mode};
 
         // Invalidate content based refresh rate selection so it could be calculated
         // again for the new refresh rate.
         mPolicy.contentRequirements.clear();
     }
-    onNonPrimaryDisplayModeChanged(handle, mode);
+    onNonPrimaryDisplayModeChanged(cycle, mode);
 }
 
 void Scheduler::dispatchCachedReportedMode() {
@@ -502,39 +443,25 @@
     }
 
     mPolicy.cachedModeChangedParams->mode = *mPolicy.modeOpt;
-    onNonPrimaryDisplayModeChanged(mPolicy.cachedModeChangedParams->handle,
+    onNonPrimaryDisplayModeChanged(mPolicy.cachedModeChangedParams->cycle,
                                    mPolicy.cachedModeChangedParams->mode);
 }
 
-void Scheduler::onNonPrimaryDisplayModeChanged(ConnectionHandle handle, const FrameRateMode& mode) {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
+void Scheduler::onNonPrimaryDisplayModeChanged(Cycle cycle, const FrameRateMode& mode) {
+    if (hasEventThreads()) {
+        eventThreadFor(cycle).onModeChanged(mode);
     }
-    thread->onModeChanged(mode);
 }
 
-void Scheduler::dump(ConnectionHandle handle, std::string& result) const {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections.at(handle).thread.get();
-    }
-    thread->dump(result);
+void Scheduler::dump(Cycle cycle, std::string& result) const {
+    eventThreadFor(cycle).dump(result);
 }
 
-void Scheduler::setDuration(ConnectionHandle handle, std::chrono::nanoseconds workDuration,
+void Scheduler::setDuration(Cycle cycle, std::chrono::nanoseconds workDuration,
                             std::chrono::nanoseconds readyDuration) {
-    android::EventThread* thread;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        RETURN_IF_INVALID_HANDLE(handle);
-        thread = mConnections[handle].thread.get();
+    if (hasEventThreads()) {
+        eventThreadFor(cycle).setDuration(workDuration, readyDuration);
     }
-    thread->setDuration(workDuration, readyDuration);
 }
 
 void Scheduler::updatePhaseConfiguration(Fps refreshRate) {
@@ -557,10 +484,10 @@
 }
 
 void Scheduler::setVsyncConfig(const VsyncConfig& config, Period vsyncPeriod) {
-    setDuration(mAppConnectionHandle,
+    setDuration(Cycle::Render,
                 /* workDuration */ config.appWorkDuration,
                 /* readyDuration */ config.sfWorkDuration);
-    setDuration(mSfConnectionHandle,
+    setDuration(Cycle::LastComposite,
                 /* workDuration */ vsyncPeriod,
                 /* readyDuration */ config.sfWorkDuration);
     setDuration(config.sfWorkDuration);
@@ -1027,16 +954,10 @@
 
 void Scheduler::applyNewVsyncSchedule(std::shared_ptr<VsyncSchedule> vsyncSchedule) {
     onNewVsyncSchedule(vsyncSchedule->getDispatch());
-    std::vector<android::EventThread*> threads;
-    {
-        std::lock_guard<std::mutex> lock(mConnectionsLock);
-        threads.reserve(mConnections.size());
-        for (auto& [_, connection] : mConnections) {
-            threads.push_back(connection.thread.get());
-        }
-    }
-    for (auto* thread : threads) {
-        thread->onNewVsyncSchedule(vsyncSchedule);
+
+    if (hasEventThreads()) {
+        eventThreadFor(Cycle::Render).onNewVsyncSchedule(vsyncSchedule);
+        eventThreadFor(Cycle::LastComposite).onNewVsyncSchedule(vsyncSchedule);
     }
 }
 
diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 9f29e9f..71df507 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -56,35 +56,6 @@
 
 #include <FrontEnd/LayerHierarchy.h>
 
-namespace android::scheduler {
-
-// Opaque handle to scheduler connection.
-struct ConnectionHandle {
-    using Id = std::uintptr_t;
-    static constexpr Id INVALID_ID = static_cast<Id>(-1);
-
-    Id id = INVALID_ID;
-
-    explicit operator bool() const { return id != INVALID_ID; }
-};
-
-inline bool operator==(ConnectionHandle lhs, ConnectionHandle rhs) {
-    return lhs.id == rhs.id;
-}
-
-} // namespace android::scheduler
-
-namespace std {
-
-template <>
-struct hash<android::scheduler::ConnectionHandle> {
-    size_t operator()(android::scheduler::ConnectionHandle handle) const {
-        return hash<android::scheduler::ConnectionHandle::Id>()(handle.id);
-    }
-};
-
-} // namespace std
-
 namespace android {
 
 class FenceTime;
@@ -106,6 +77,11 @@
 class VsyncConfiguration;
 class VsyncSchedule;
 
+enum class Cycle {
+    Render,       // Surface rendering.
+    LastComposite // Ahead of display compositing by one refresh period.
+};
+
 class Scheduler : public IEventThreadCallback, android::impl::MessageQueue {
     using Impl = android::impl::MessageQueue;
 
@@ -154,36 +130,32 @@
         return std::move(future);
     }
 
-    enum class Cycle {
-        Render,       // Surface rendering.
-        LastComposite // Ahead of display compositing by one refresh period.
-    };
-
-    ConnectionHandle createEventThread(Cycle, frametimeline::TokenManager*,
-                                       std::chrono::nanoseconds workDuration,
-                                       std::chrono::nanoseconds readyDuration);
+    void createEventThread(Cycle, frametimeline::TokenManager*,
+                           std::chrono::nanoseconds workDuration,
+                           std::chrono::nanoseconds readyDuration);
 
     sp<IDisplayEventConnection> createDisplayEventConnection(
-            ConnectionHandle, EventRegistrationFlags eventRegistration = {},
+            Cycle, EventRegistrationFlags eventRegistration = {},
             const sp<IBinder>& layerHandle = nullptr) EXCLUDES(mChoreographerLock);
 
-    sp<EventThreadConnection> getEventConnection(ConnectionHandle);
+    const sp<EventThreadConnection>& getEventConnection(Cycle cycle) const {
+        return cycle == Cycle::Render ? mRenderEventConnection : mLastCompositeEventConnection;
+    }
 
-    void onHotplugReceived(ConnectionHandle, PhysicalDisplayId, bool connected);
-    void onHotplugConnectionError(ConnectionHandle, int32_t errorCode);
+    void onHotplugReceived(Cycle, PhysicalDisplayId, bool connected);
+    void onHotplugConnectionError(Cycle, int32_t errorCode);
 
-    void onPrimaryDisplayModeChanged(ConnectionHandle, const FrameRateMode&) EXCLUDES(mPolicyLock);
-    void onNonPrimaryDisplayModeChanged(ConnectionHandle, const FrameRateMode&);
+    void onPrimaryDisplayModeChanged(Cycle, const FrameRateMode&) EXCLUDES(mPolicyLock);
+    void onNonPrimaryDisplayModeChanged(Cycle, const FrameRateMode&);
 
     void enableSyntheticVsync(bool = true) REQUIRES(kMainThreadContext);
 
-    void onFrameRateOverridesChanged(ConnectionHandle, PhysicalDisplayId)
-            EXCLUDES(mConnectionsLock);
+    void onFrameRateOverridesChanged(Cycle, PhysicalDisplayId);
 
-    void onHdcpLevelsChanged(ConnectionHandle, PhysicalDisplayId, int32_t, int32_t);
+    void onHdcpLevelsChanged(Cycle, PhysicalDisplayId, int32_t, int32_t);
 
     // Modifies work duration in the event thread.
-    void setDuration(ConnectionHandle, std::chrono::nanoseconds workDuration,
+    void setDuration(Cycle, std::chrono::nanoseconds workDuration,
                      std::chrono::nanoseconds readyDuration);
 
     VsyncModulator& vsyncModulator() { return *mVsyncModulator; }
@@ -288,7 +260,7 @@
     bool isVsyncInPhase(TimePoint expectedVsyncTime, Fps frameRate) const;
 
     void dump(utils::Dumper&) const;
-    void dump(ConnectionHandle, std::string&) const;
+    void dump(Cycle, std::string&) const;
     void dumpVsync(std::string&) const EXCLUDES(mDisplayLock);
 
     // Returns the preferred refresh rate and frame rate for the pacesetter display.
@@ -369,8 +341,15 @@
     void onFrameSignal(ICompositor&, VsyncId, TimePoint expectedVsyncTime) override
             REQUIRES(kMainThreadContext, mDisplayLock);
 
-    // Create a connection on the given EventThread.
-    ConnectionHandle createConnection(std::unique_ptr<EventThread>);
+    // Used to skip event dispatch before EventThread creation during boot.
+    // TODO: b/241285191 - Reorder Scheduler initialization to avoid this.
+    bool hasEventThreads() const {
+        return CC_LIKELY(mRenderEventThread && mLastCompositeEventThread);
+    }
+
+    EventThread& eventThreadFor(Cycle cycle) const {
+        return *(cycle == Cycle::Render ? mRenderEventThread : mLastCompositeEventThread);
+    }
 
     // Update feature state machine to given state when corresponding timer resets or expires.
     void kernelIdleTimerCallback(TimerState) EXCLUDES(mDisplayLock);
@@ -460,18 +439,11 @@
     void resync() override EXCLUDES(mDisplayLock);
     void onExpectedPresentTimePosted(TimePoint expectedPresentTime) override EXCLUDES(mDisplayLock);
 
-    // Stores EventThread associated with a given VSyncSource, and an initial EventThreadConnection.
-    struct Connection {
-        sp<EventThreadConnection> connection;
-        std::unique_ptr<EventThread> thread;
-    };
+    std::unique_ptr<EventThread> mRenderEventThread;
+    sp<EventThreadConnection> mRenderEventConnection;
 
-    ConnectionHandle::Id mNextConnectionHandleId = 0;
-    mutable std::mutex mConnectionsLock;
-    std::unordered_map<ConnectionHandle, Connection> mConnections GUARDED_BY(mConnectionsLock);
-
-    ConnectionHandle mAppConnectionHandle;
-    ConnectionHandle mSfConnectionHandle;
+    std::unique_ptr<EventThread> mLastCompositeEventThread;
+    sp<EventThreadConnection> mLastCompositeEventConnection;
 
     std::atomic<nsecs_t> mLastResyncTime = 0;
 
@@ -585,7 +557,7 @@
         ftl::Optional<FrameRateMode> modeOpt;
 
         struct ModeChangedParams {
-            ConnectionHandle handle;
+            Cycle cycle;
             FrameRateMode mode;
         };
 
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e44f841..ecb266d 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2085,12 +2085,11 @@
 sp<IDisplayEventConnection> SurfaceFlinger::createDisplayEventConnection(
         gui::ISurfaceComposer::VsyncSource vsyncSource, EventRegistrationFlags eventRegistration,
         const sp<IBinder>& layerHandle) {
-    const auto& handle =
-            vsyncSource == gui::ISurfaceComposer::VsyncSource::eVsyncSourceSurfaceFlinger
-            ? mSfConnectionHandle
-            : mAppConnectionHandle;
+    const auto cycle = vsyncSource == gui::ISurfaceComposer::VsyncSource::eVsyncSourceSurfaceFlinger
+            ? scheduler::Cycle::LastComposite
+            : scheduler::Cycle::Render;
 
-    return mScheduler->createDisplayEventConnection(handle, eventRegistration, layerHandle);
+    return mScheduler->createDisplayEventConnection(cycle, eventRegistration, layerHandle);
 }
 
 void SurfaceFlinger::scheduleCommit(FrameHint hint) {
@@ -2132,7 +2131,7 @@
             const int32_t hotplugErrorCode = static_cast<int32_t>(-timestamp);
             ALOGD("SurfaceFlinger got hotplugErrorCode=%d for display %" PRIu64, hotplugErrorCode,
                   hwcDisplayId);
-            mScheduler->onHotplugConnectionError(mAppConnectionHandle, hotplugErrorCode);
+            mScheduler->onHotplugConnectionError(scheduler::Cycle::Render, hotplugErrorCode);
             return;
         }
 
@@ -2183,7 +2182,7 @@
     if (FlagManager::getInstance().hotplug2()) {
         ALOGD("SurfaceFlinger got hotplug event=%d", static_cast<int32_t>(event));
         // TODO(b/311403559): use enum type instead of int
-        mScheduler->onHotplugConnectionError(mAppConnectionHandle, static_cast<int32_t>(event));
+        mScheduler->onHotplugConnectionError(scheduler::Cycle::Render, static_cast<int32_t>(event));
     }
 }
 
@@ -3473,7 +3472,7 @@
     if (!activeMode) {
         ALOGE("Failed to hotplug display %s", to_string(displayId).c_str());
         if (FlagManager::getInstance().hotplug2()) {
-            mScheduler->onHotplugConnectionError(mAppConnectionHandle,
+            mScheduler->onHotplugConnectionError(scheduler::Cycle::Render,
                                                  static_cast<int32_t>(
                                                          DisplayHotplugEvent::ERROR_UNKNOWN));
         }
@@ -3526,8 +3525,8 @@
 }
 
 void SurfaceFlinger::dispatchDisplayHotplugEvent(PhysicalDisplayId displayId, bool connected) {
-    mScheduler->onHotplugReceived(mAppConnectionHandle, displayId, connected);
-    mScheduler->onHotplugReceived(mSfConnectionHandle, displayId, connected);
+    mScheduler->onHotplugReceived(scheduler::Cycle::Render, displayId, connected);
+    mScheduler->onHotplugReceived(scheduler::Cycle::LastComposite, displayId, connected);
 }
 
 void SurfaceFlinger::dispatchDisplayModeChangeEvent(PhysicalDisplayId displayId,
@@ -3537,7 +3536,7 @@
             ? &scheduler::Scheduler::onPrimaryDisplayModeChanged
             : &scheduler::Scheduler::onNonPrimaryDisplayModeChanged;
 
-    ((*mScheduler).*onDisplayModeChanged)(mAppConnectionHandle, mode);
+    ((*mScheduler).*onDisplayModeChanged)(scheduler::Cycle::Render, mode);
 }
 
 sp<DisplayDevice> SurfaceFlinger::setupNewDisplayDeviceInternal(
@@ -4189,7 +4188,7 @@
         return getDefaultDisplayDeviceLocked()->getPhysicalId();
     }();
 
-    mScheduler->onFrameRateOverridesChanged(mAppConnectionHandle, displayId);
+    mScheduler->onFrameRateOverridesChanged(scheduler::Cycle::Render, displayId);
 }
 
 void SurfaceFlinger::notifyCpuLoadUp() {
@@ -4354,24 +4353,22 @@
     mScheduler = std::make_unique<Scheduler>(static_cast<ICompositor&>(*this),
                                              static_cast<ISchedulerCallback&>(*this), features,
                                              getFactory(), activeRefreshRate, *mTimeStats);
+
+    // The pacesetter must be registered before EventThread creation below.
     mScheduler->registerDisplay(display->getPhysicalId(), display->holdRefreshRateSelector());
     if (FlagManager::getInstance().vrr_config()) {
         mScheduler->setRenderRate(display->getPhysicalId(), activeMode.fps);
     }
-    mScheduler->startTimers();
 
     const auto configs = mScheduler->getVsyncConfiguration().getCurrentConfigs();
 
-    mAppConnectionHandle =
-            mScheduler->createEventThread(Scheduler::Cycle::Render,
-                                          mFrameTimeline->getTokenManager(),
-                                          /* workDuration */ configs.late.appWorkDuration,
-                                          /* readyDuration */ configs.late.sfWorkDuration);
-    mSfConnectionHandle =
-            mScheduler->createEventThread(Scheduler::Cycle::LastComposite,
-                                          mFrameTimeline->getTokenManager(),
-                                          /* workDuration */ activeRefreshRate.getPeriod(),
-                                          /* readyDuration */ configs.late.sfWorkDuration);
+    mScheduler->createEventThread(scheduler::Cycle::Render, mFrameTimeline->getTokenManager(),
+                                  /* workDuration */ configs.late.appWorkDuration,
+                                  /* readyDuration */ configs.late.sfWorkDuration);
+    mScheduler->createEventThread(scheduler::Cycle::LastComposite,
+                                  mFrameTimeline->getTokenManager(),
+                                  /* workDuration */ activeRefreshRate.getPeriod(),
+                                  /* readyDuration */ configs.late.sfWorkDuration);
 
     mScheduler->initVsync(*mFrameTimeline->getTokenManager(), configs.late.sfWorkDuration);
 
@@ -4379,6 +4376,9 @@
             sp<RegionSamplingThread>::make(*this,
                                            RegionSamplingThread::EnvironmentTimingTunables());
     mFpsReporter = sp<FpsReporter>::make(*mFrameTimeline);
+
+    // Timer callbacks may fire, so do this last.
+    mScheduler->startTimers();
 }
 
 void SurfaceFlinger::doCommitTransactions() {
@@ -6315,7 +6315,7 @@
 }
 
 void SurfaceFlinger::dumpEvents(std::string& result) const {
-    mScheduler->dump(mAppConnectionHandle, result);
+    mScheduler->dump(scheduler::Cycle::Render, result);
 }
 
 void SurfaceFlinger::dumpVsync(std::string& result) const {
@@ -7087,14 +7087,15 @@
                 mForceFullDamage = n != 0;
                 return NO_ERROR;
             }
-            case 1018: { // Modify Choreographer's duration
+            case 1018: { // Set the render deadline as a duration until VSYNC.
                 n = data.readInt32();
-                mScheduler->setDuration(mAppConnectionHandle, std::chrono::nanoseconds(n), 0ns);
+                mScheduler->setDuration(scheduler::Cycle::Render, std::chrono::nanoseconds(n), 0ns);
                 return NO_ERROR;
             }
-            case 1019: { // Modify SurfaceFlinger's duration
+            case 1019: { // Set the deadline of the last composite as a duration until VSYNC.
                 n = data.readInt32();
-                mScheduler->setDuration(mSfConnectionHandle, std::chrono::nanoseconds(n), 0ns);
+                mScheduler->setDuration(scheduler::Cycle::LastComposite,
+                                        std::chrono::nanoseconds(n), 0ns);
                 return NO_ERROR;
             }
             case 1020: { // Unused
@@ -7326,7 +7327,7 @@
                 auto inUid = static_cast<uid_t>(data.readInt32());
                 const auto refreshRate = data.readFloat();
                 mScheduler->setPreferredRefreshRateForUid(FrameRateOverride{inUid, refreshRate});
-                mScheduler->onFrameRateOverridesChanged(mAppConnectionHandle, displayId);
+                mScheduler->onFrameRateOverridesChanged(scheduler::Cycle::Render, displayId);
                 return NO_ERROR;
             }
             // Toggle caching feature
@@ -8466,10 +8467,10 @@
     // TODO(b/140204874): Leave the event in until we do proper testing with all apps that might
     // be depending in this callback.
     if (const auto activeMode = selector.getActiveMode(); displayId == mActiveDisplayId) {
-        mScheduler->onPrimaryDisplayModeChanged(mAppConnectionHandle, activeMode);
+        mScheduler->onPrimaryDisplayModeChanged(scheduler::Cycle::Render, activeMode);
         toggleKernelIdleTimer();
     } else {
-        mScheduler->onNonPrimaryDisplayModeChanged(mAppConnectionHandle, activeMode);
+        mScheduler->onNonPrimaryDisplayModeChanged(scheduler::Cycle::Render, activeMode);
     }
 
     auto preferredModeOpt = getPreferredDisplayMode(displayId, currentPolicy.defaultMode);
@@ -8657,7 +8658,7 @@
     }();
 
     mScheduler->setGameModeFrameRateForUid(FrameRateOverride{static_cast<uid_t>(uid), frameRate});
-    mScheduler->onFrameRateOverridesChanged(mAppConnectionHandle, displayId);
+    mScheduler->onFrameRateOverridesChanged(scheduler::Cycle::Render, displayId);
     return NO_ERROR;
 }
 
@@ -8919,7 +8920,8 @@
             Mutex::Autolock lock(mStateLock);
             display->setSecure(connectedLevel >= 2 /* HDCP_V1 */);
         }
-        mScheduler->onHdcpLevelsChanged(mAppConnectionHandle, displayId, connectedLevel, maxLevel);
+        mScheduler->onHdcpLevelsChanged(scheduler::Cycle::Render, displayId, connectedLevel,
+                                        maxLevel);
     }));
 }
 
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index be05797..b01d1aa 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1356,12 +1356,7 @@
 
     const std::string mHwcServiceName;
 
-    /*
-     * Scheduler
-     */
     std::unique_ptr<scheduler::Scheduler> mScheduler;
-    scheduler::ConnectionHandle mAppConnectionHandle;
-    scheduler::ConnectionHandle mSfConnectionHandle;
 
     scheduler::PresentLatencyTracker mPresentLatencyTracker GUARDED_BY(kMainThreadContext);
 
diff --git a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
index b059525..10e2220 100644
--- a/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/SchedulerTest.cpp
@@ -99,7 +99,6 @@
     TestableScheduler* mScheduler = new TestableScheduler{mSelector, mFlinger, mSchedulerCallback};
     surfaceflinger::frontend::LayerHierarchyBuilder mLayerHierarchyBuilder;
 
-    ConnectionHandle mConnectionHandle;
     MockEventThread* mEventThread;
     sp<MockEventThreadConnection> mEventThreadConnection;
 };
@@ -116,54 +115,13 @@
     EXPECT_CALL(*mEventThread, createEventConnection(_, _))
             .WillRepeatedly(Return(mEventThreadConnection));
 
-    mConnectionHandle = mScheduler->createConnection(std::move(eventThread));
-    EXPECT_TRUE(mConnectionHandle);
+    mScheduler->setEventThread(Cycle::Render, std::move(eventThread));
 
     mFlinger.resetScheduler(mScheduler);
 }
 
 } // namespace
 
-TEST_F(SchedulerTest, invalidConnectionHandle) {
-    ConnectionHandle handle;
-
-    const sp<IDisplayEventConnection> connection = mScheduler->createDisplayEventConnection(handle);
-
-    EXPECT_FALSE(connection);
-    EXPECT_FALSE(mScheduler->getEventConnection(handle));
-
-    // The EXPECT_CALLS make sure we don't call the functions on the subsequent event threads.
-    EXPECT_CALL(*mEventThread, onHotplugReceived(_, _)).Times(0);
-    mScheduler->onHotplugReceived(handle, kDisplayId1, false);
-
-    std::string output;
-    EXPECT_CALL(*mEventThread, dump(_)).Times(0);
-    mScheduler->dump(handle, output);
-    EXPECT_TRUE(output.empty());
-
-    EXPECT_CALL(*mEventThread, setDuration(10ns, 20ns)).Times(0);
-    mScheduler->setDuration(handle, 10ns, 20ns);
-}
-
-TEST_F(SchedulerTest, validConnectionHandle) {
-    const sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle);
-
-    ASSERT_EQ(mEventThreadConnection, connection);
-    EXPECT_TRUE(mScheduler->getEventConnection(mConnectionHandle));
-
-    EXPECT_CALL(*mEventThread, onHotplugReceived(kDisplayId1, false)).Times(1);
-    mScheduler->onHotplugReceived(mConnectionHandle, kDisplayId1, false);
-
-    std::string output("dump");
-    EXPECT_CALL(*mEventThread, dump(output)).Times(1);
-    mScheduler->dump(mConnectionHandle, output);
-    EXPECT_FALSE(output.empty());
-
-    EXPECT_CALL(*mEventThread, setDuration(10ns, 20ns)).Times(1);
-    mScheduler->setDuration(mConnectionHandle, 10ns, 20ns);
-}
-
 TEST_F(SchedulerTest, registerDisplay) FTL_FAKE_GUARD(kMainThreadContext) {
     // Hardware VSYNC should not change if the display is already registered.
     EXPECT_CALL(mSchedulerCallback, requestHardwareVsync(kDisplayId1, false)).Times(0);
@@ -235,22 +193,6 @@
     EXPECT_NO_FATAL_FAILURE(mScheduler->dispatchCachedReportedMode());
 }
 
-TEST_F(SchedulerTest, onNonPrimaryDisplayModeChanged_invalidParameters) {
-    const auto mode = DisplayMode::Builder(hal::HWConfigId(0))
-                              .setId(DisplayModeId(111))
-                              .setPhysicalDisplayId(kDisplayId1)
-                              .setVsyncPeriod(111111)
-                              .build();
-
-    // If the handle is incorrect, the function should return before
-    // onModeChange is called.
-    ConnectionHandle invalidHandle = {.id = 123};
-    EXPECT_NO_FATAL_FAILURE(
-            mScheduler->onNonPrimaryDisplayModeChanged(invalidHandle,
-                                                       {90_Hz, ftl::as_non_null(mode)}));
-    EXPECT_CALL(*mEventThread, onModeChanged(_)).Times(0);
-}
-
 TEST_F(SchedulerTest, calculateMaxAcquiredBufferCount) {
     EXPECT_EQ(1, mFlinger.calculateMaxAcquiredBufferCount(60_Hz, 30ms));
     EXPECT_EQ(2, mFlinger.calculateMaxAcquiredBufferCount(90_Hz, 30ms));
@@ -753,7 +695,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     const sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     EXPECT_EQ(1u, mScheduler->mutableAttachedChoreographers().size());
     ASSERT_EQ(1u, mScheduler->mutableAttachedChoreographers().count(layer->getSequence()));
@@ -782,9 +724,9 @@
             .WillOnce(Return(mockConnection2));
 
     const sp<IDisplayEventConnection> connection1 =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, handle);
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, handle);
     const sp<IDisplayEventConnection> connection2 =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, handle);
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, handle);
 
     EXPECT_EQ(1u, mScheduler->mutableAttachedChoreographers().size());
     ASSERT_EQ(1u, mScheduler->mutableAttachedChoreographers().count(layer->getSequence()));
@@ -802,9 +744,9 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached).Times(2);
     const sp<IDisplayEventConnection> connection1 =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer1->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer1->getHandle());
     const sp<IDisplayEventConnection> connection2 =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer2->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer2->getHandle());
 
     EXPECT_EQ(2u, mScheduler->mutableAttachedChoreographers().size());
 
@@ -831,7 +773,7 @@
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
 
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     ASSERT_EQ(1u, mScheduler->mutableAttachedChoreographers().count(layer->getSequence()));
     EXPECT_EQ(1u,
@@ -861,7 +803,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     const sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     layer.clear();
     mFlinger.mutableLayersPendingRemoval().clear();
@@ -875,7 +817,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     RequestedLayerState layerState(LayerCreationArgs(layer->getSequence()));
     LayerHierarchy hierarchy(&layerState);
@@ -935,7 +877,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, parent->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, parent->getHandle());
 
     RequestedLayerState parentState(LayerCreationArgs(parent->getSequence()));
     LayerHierarchy parentHierarchy(&parentState);
@@ -962,7 +904,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, parent->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, parent->getHandle());
 
     RequestedLayerState parentState(LayerCreationArgs(parent->getSequence()));
     LayerHierarchy parentHierarchy(&parentState);
@@ -997,7 +939,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, parent->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, parent->getHandle());
 
     RequestedLayerState parentState(LayerCreationArgs(parent->getSequence()));
     LayerHierarchy parentHierarchy(&parentState);
@@ -1031,7 +973,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     RequestedLayerState parentState(LayerCreationArgs(parent->getSequence()));
     LayerHierarchy parentHierarchy(&parentState);
@@ -1057,7 +999,7 @@
 
     EXPECT_CALL(mSchedulerCallback, onChoreographerAttached);
     sp<IDisplayEventConnection> connection =
-            mScheduler->createDisplayEventConnection(mConnectionHandle, {}, layer->getHandle());
+            mScheduler->createDisplayEventConnection(Cycle::Render, {}, layer->getHandle());
 
     RequestedLayerState parentState(LayerCreationArgs(parent->getSequence()));
     LayerHierarchy parentHierarchy(&parentState);
diff --git a/services/surfaceflinger/tests/unittests/TestableScheduler.h b/services/surfaceflinger/tests/unittests/TestableScheduler.h
index 25a85df..1472ebf 100644
--- a/services/surfaceflinger/tests/unittests/TestableScheduler.h
+++ b/services/surfaceflinger/tests/unittests/TestableScheduler.h
@@ -71,9 +71,14 @@
         Scheduler::onFrameSignal(compositor, vsyncId, TimePoint());
     }
 
-    // Used to inject mock event thread.
-    ConnectionHandle createConnection(std::unique_ptr<EventThread> eventThread) {
-        return Scheduler::createConnection(std::move(eventThread));
+    void setEventThread(Cycle cycle, std::unique_ptr<EventThread> eventThreadPtr) {
+        if (cycle == Cycle::Render) {
+            mRenderEventThread = std::move(eventThreadPtr);
+            mRenderEventConnection = mRenderEventThread->createEventConnection();
+        } else {
+            mLastCompositeEventThread = std::move(eventThreadPtr);
+            mLastCompositeEventConnection = mLastCompositeEventThread->createEventConnection();
+        }
     }
 
     auto refreshRateSelector() { return pacesetterSelectorPtr(); }
@@ -124,7 +129,6 @@
 
     using Scheduler::resyncAllToHardwareVsync;
 
-    auto& mutableAppConnectionHandle() { return mAppConnectionHandle; }
     auto& mutableLayerHistory() { return mLayerHistory; }
     auto& mutableAttachedChoreographers() { return mAttachedChoreographers; }
 
@@ -180,10 +184,6 @@
         mPolicy.cachedModeChangedParams.reset();
     }
 
-    void onNonPrimaryDisplayModeChanged(ConnectionHandle handle, const FrameRateMode& mode) {
-        Scheduler::onNonPrimaryDisplayModeChanged(handle, mode);
-    }
-
     void setInitialHwVsyncEnabled(PhysicalDisplayId id, bool enabled) {
         auto schedule = getVsyncSchedule(id);
         std::lock_guard<std::mutex> lock(schedule->mHwVsyncLock);
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 46a079c..bce7729 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -258,11 +258,9 @@
 
         mScheduler->initVsync(*mTokenManager, 0ms);
 
-        mScheduler->mutableAppConnectionHandle() =
-                mScheduler->createConnection(std::move(appEventThread));
+        mScheduler->setEventThread(scheduler::Cycle::Render, std::move(appEventThread));
+        mScheduler->setEventThread(scheduler::Cycle::LastComposite, std::move(sfEventThread));
 
-        mFlinger->mAppConnectionHandle = mScheduler->mutableAppConnectionHandle();
-        mFlinger->mSfConnectionHandle = mScheduler->createConnection(std::move(sfEventThread));
         resetScheduler(mScheduler);
     }