diff --git a/include/ui/Fence.h b/include/ui/Fence.h
index 1df15f8..99b39d8 100644
--- a/include/ui/Fence.h
+++ b/include/ui/Fence.h
@@ -42,6 +42,11 @@
 {
 public:
     static const sp<Fence> NO_FENCE;
+    static constexpr nsecs_t SIGNAL_TIME_PENDING = INT64_MAX;
+    static constexpr nsecs_t SIGNAL_TIME_INVALID = -1;
+    static inline bool isValidTimestamp(nsecs_t time) {
+        return time >= 0 && time < INT64_MAX;
+    }
 
     // TIMEOUT_NEVER may be passed to the wait method to indicate that it
     // should wait indefinitely for the fence to signal.
@@ -94,8 +99,8 @@
 
     // getSignalTime returns the system monotonic clock time at which the
     // fence transitioned to the signaled state.  If the fence is not signaled
-    // then INT64_MAX is returned.  If the fence is invalid or if an error
-    // occurs then -1 is returned.
+    // then SIGNAL_TIME_PENDING is returned.  If the fence is invalid or if an
+    // error occurs then SIGNAL_TIME_INVALID is returned.
     nsecs_t getSignalTime() const;
 
 #if __cplusplus > 201103L
diff --git a/include/ui/FenceTime.h b/include/ui/FenceTime.h
new file mode 100644
index 0000000..27cc720
--- /dev/null
+++ b/include/ui/FenceTime.h
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_FENCE_TIME_H
+#define ANDROID_FENCE_TIME_H
+
+#include <ui/Fence.h>
+#include <utils/Flattenable.h>
+#include <utils/Timers.h>
+
+#include <atomic>
+#include <mutex>
+#include <queue>
+
+namespace android {
+
+// A wrapper around fence that only implements isValid and getSignalTime.
+// It automatically closes the fence in a thread-safe manner once the signal
+// time is known.
+class FenceTime {
+public:
+    // An atomic snapshot of the FenceTime that is flattenable.
+    //
+    // This class is needed because the FenceTime class may not stay
+    // consistent for all steps of the flattening process.
+    //
+    // Not thread safe.
+    struct Snapshot : public Flattenable<Snapshot> {
+        enum class State {
+            EMPTY,
+            FENCE,
+            SIGNAL_TIME,
+        };
+
+        Snapshot() = default;  // Creates an empty snapshot.
+        explicit Snapshot(const sp<Fence>& fence);
+        explicit Snapshot(nsecs_t signalTime);
+
+        // Movable.
+        Snapshot(Snapshot&& src) = default;
+        Snapshot& operator=(Snapshot&& src) = default;
+        // Not copyable.
+        Snapshot(const Snapshot& src) = delete;
+        Snapshot& operator=(const Snapshot&& src) = delete;
+
+        // Flattenable implementation.
+        size_t getFlattenedSize() const;
+        size_t getFdCount() const;
+        status_t flatten(void*& buffer, size_t& size, int*& fds,
+                size_t& count) const;
+        status_t unflatten(void const*& buffer, size_t& size, int const*& fds,
+                size_t& count);
+
+        State state{State::EMPTY};
+        sp<Fence> fence{Fence::NO_FENCE};
+        nsecs_t signalTime{Fence::SIGNAL_TIME_INVALID};
+    };
+
+    static const std::shared_ptr<FenceTime> NO_FENCE;
+
+    explicit FenceTime(const sp<Fence>& fence);
+    explicit FenceTime(sp<Fence>&& fence);
+
+    // Passing in Fence::SIGNAL_TIME_PENDING is not allowed.
+    // Doing so will convert the signalTime to Fence::SIGNAL_TIME_INVALID.
+    explicit FenceTime(nsecs_t signalTime);
+
+    // Do not allow default construction. Share NO_FENCE or explicitly construct
+    // with Fence::SIGNAL_TIME_INVALID instead.
+    FenceTime() = delete;
+
+    // Do not allow copy, assign, or move. Use a shared_ptr to share the
+    // signalTime result. Or use getSnapshot() if a thread-safe copy is really
+    // needed.
+    FenceTime(const FenceTime&) = delete;
+    FenceTime(FenceTime&&) = delete;
+    FenceTime& operator=(const FenceTime&) = delete;
+    FenceTime& operator=(FenceTime&&) = delete;
+
+    // This method should only be called when replacing the fence with
+    // a signalTime. Since this is an indirect way of setting the signal time
+    // of a fence, the snapshot should come from a trusted source.
+    void applyTrustedSnapshot(const Snapshot& src);
+
+    bool isValid() const;
+
+    // Attempts to get the timestamp from the Fence if the timestamp isn't
+    // already cached. Otherwise, it returns the cached value.
+    nsecs_t getSignalTime();
+
+    // Gets the cached timestamp without attempting to query the Fence.
+    nsecs_t getCachedSignalTime() const;
+
+    // Returns a snapshot of the FenceTime in its current state.
+    Snapshot getSnapshot() const;
+
+    // Override new and delete since this needs 8-byte alignment, which
+    // is not guaranteed on x86.
+    static void* operator new(size_t nbytes) noexcept;
+    static void operator delete(void *p);
+
+private:
+    enum class State {
+        VALID,
+        INVALID,
+    };
+
+    const State mState{State::INVALID};
+
+    // mMutex guards mFence and mSignalTime.
+    // mSignalTime is also atomic since it is sometimes read outside the lock
+    // for quick checks.
+    mutable std::mutex mMutex;
+    sp<Fence> mFence{Fence::NO_FENCE};
+    std::atomic<nsecs_t> mSignalTime{Fence::SIGNAL_TIME_INVALID};
+};
+
+// A queue of FenceTimes that are expected to signal in FIFO order.
+// Only maintains a queue of weak pointers so it doesn't keep references
+// to Fences on its own.
+//
+// Can be used to get the signal time of a fence and close its file descriptor
+// without making a syscall for every fence later in the timeline.
+// Additionally, since the FenceTime caches the timestamp internally,
+// other timelines that reference the same FenceTime can avoid the syscall.
+//
+// FenceTimeline only keeps track of a limited number of entries to avoid
+// growing unbounded. Users of FenceTime must make sure they can work even
+// if FenceTimeline did nothing. i.e. they should eventually call
+// Fence::getSignalTime(), not only Fence::getCachedSignalTime().
+//
+// push() and updateSignalTimes() are safe to call simultaneously from
+// different threads.
+class FenceTimeline {
+public:
+    static constexpr size_t MAX_ENTRIES = 64;
+
+    void push(const std::shared_ptr<FenceTime>& fence);
+    void updateSignalTimes();
+
+private:
+    mutable std::mutex mMutex;
+    std::queue<std::weak_ptr<FenceTime>> mQueue;
+};
+
+}; // namespace android
+
+#endif // ANDROID_FENCE_TIME_H
diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index 087e877..661d1c8 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -43,6 +43,7 @@
     srcs: [
         "ColorSpace.cpp",
         "Fence.cpp",
+        "FenceTime.cpp",
         "FrameStats.cpp",
         "Gralloc1.cpp",
         "Gralloc1On0Adapter.cpp",
diff --git a/libs/ui/Fence.cpp b/libs/ui/Fence.cpp
index 7cf8233..a1dda3a 100644
--- a/libs/ui/Fence.cpp
+++ b/libs/ui/Fence.cpp
@@ -109,17 +109,17 @@
 
 nsecs_t Fence::getSignalTime() const {
     if (mFenceFd == -1) {
-        return -1;
+        return SIGNAL_TIME_INVALID;
     }
 
     struct sync_fence_info_data* finfo = sync_fence_info(mFenceFd);
     if (finfo == NULL) {
         ALOGE("sync_fence_info returned NULL for fd %d", mFenceFd);
-        return -1;
+        return SIGNAL_TIME_INVALID;
     }
     if (finfo->status != 1) {
         sync_fence_info_free(finfo);
-        return INT64_MAX;
+        return SIGNAL_TIME_PENDING;
     }
 
     struct sync_pt_info* pinfo = NULL;
diff --git a/libs/ui/FenceTime.cpp b/libs/ui/FenceTime.cpp
new file mode 100644
index 0000000..c0245eb
--- /dev/null
+++ b/libs/ui/FenceTime.cpp
@@ -0,0 +1,282 @@
+/*
+* Copyright 2016 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.
+*/
+
+#include <ui/FenceTime.h>
+
+#include <cutils/compiler.h>  // For CC_[UN]LIKELY
+#include <inttypes.h>
+#include <stdlib.h>
+
+#include <memory>
+
+namespace android {
+
+// ============================================================================
+// FenceTime
+// ============================================================================
+
+const auto FenceTime::NO_FENCE = std::make_shared<FenceTime>(Fence::NO_FENCE);
+
+void* FenceTime::operator new(size_t byteCount) noexcept {
+    void *p = nullptr;
+    if (posix_memalign(&p, alignof(FenceTime), byteCount)) {
+        return nullptr;
+    }
+    return p;
+}
+
+void FenceTime::operator delete(void *p) {
+    free(p);
+}
+
+FenceTime::FenceTime(const sp<Fence>& fence)
+  : mState(((fence.get() != nullptr) && fence->isValid()) ?
+            State::VALID : State::INVALID),
+    mFence(fence),
+    mSignalTime(mState == State::INVALID ?
+            Fence::SIGNAL_TIME_INVALID : Fence::SIGNAL_TIME_PENDING) {
+}
+
+FenceTime::FenceTime(sp<Fence>&& fence)
+  : mState(((fence.get() != nullptr) && fence->isValid()) ?
+            State::VALID : State::INVALID),
+    mFence(std::move(fence)),
+    mSignalTime(mState == State::INVALID ?
+            Fence::SIGNAL_TIME_INVALID : Fence::SIGNAL_TIME_PENDING) {
+}
+
+FenceTime::FenceTime(nsecs_t signalTime)
+  : mState(Fence::isValidTimestamp(signalTime) ? State::VALID : State::INVALID),
+    mFence(nullptr),
+    mSignalTime(signalTime == Fence::SIGNAL_TIME_PENDING ?
+            Fence::SIGNAL_TIME_INVALID : signalTime) {
+}
+
+void FenceTime::applyTrustedSnapshot(const Snapshot& src) {
+    if (CC_UNLIKELY(src.state != Snapshot::State::SIGNAL_TIME)) {
+        // Applying Snapshot::State::FENCE, could change the valid state of the
+        // FenceTime, which is not allowed. Callers should create a new
+        // FenceTime from the snapshot instead.
+        ALOGE("FenceTime::applyTrustedSnapshot: Unexpected fence.");
+        return;
+    }
+
+    if (src.state == Snapshot::State::EMPTY) {
+        return;
+    }
+
+    nsecs_t signalTime = mSignalTime.load(std::memory_order_relaxed);
+    if (signalTime != Fence::SIGNAL_TIME_PENDING) {
+        // We should always get the same signalTime here that we did in
+        // getSignalTime(). This check races with getSignalTime(), but it is
+        // only a sanity check so that's okay.
+        if (CC_UNLIKELY(signalTime != src.signalTime)) {
+            ALOGE("FenceTime::applyTrustedSnapshot: signalTime mismatch. "
+                    "(%" PRId64 " (old) != %" PRId64 " (new))",
+                    signalTime, src.signalTime);
+        }
+        return;
+    }
+
+    std::lock_guard<std::mutex> lock(mMutex);
+    mFence.clear();
+    mSignalTime.store(src.signalTime, std::memory_order_relaxed);
+}
+
+bool FenceTime::isValid() const {
+    // We store the valid state in the constructors and return it here.
+    // This lets release code remember the valid state even after the
+    // underlying fence is destroyed.
+    return mState != State::INVALID;
+}
+
+nsecs_t FenceTime::getSignalTime() {
+    // See if we already have a cached value we can return.
+    nsecs_t signalTime = mSignalTime.load(std::memory_order_relaxed);
+    if (signalTime != Fence::SIGNAL_TIME_PENDING) {
+        return signalTime;
+    }
+
+    // Hold a reference to the fence on the stack in case the class'
+    // reference is removed by another thread. This prevents the
+    // fence from being destroyed until the end of this method, where
+    // we conveniently do not have the lock held.
+    sp<Fence> fence;
+    {
+        // With the lock acquired this time, see if we have the cached
+        // value or if we need to poll the fence.
+        std::lock_guard<std::mutex> lock(mMutex);
+        if (!mFence.get()) {
+            // Another thread set the signal time just before we added the
+            // reference to mFence.
+            return mSignalTime.load(std::memory_order_relaxed);
+        }
+        fence = mFence;
+    }
+
+    // Make the system call without the lock held.
+    signalTime = fence->getSignalTime();
+
+    // Make the signal time visible to everyone if it is no longer pending
+    // and remove the class' reference to the fence.
+    if (signalTime != Fence::SIGNAL_TIME_PENDING) {
+        std::lock_guard<std::mutex> lock(mMutex);
+        mFence.clear();
+        mSignalTime.store(signalTime, std::memory_order_relaxed);
+    }
+
+    return signalTime;
+}
+
+nsecs_t FenceTime::getCachedSignalTime() const {
+    // memory_order_acquire since we don't have a lock fallback path
+    // that will do an acquire.
+    return mSignalTime.load(std::memory_order_acquire);
+}
+
+FenceTime::Snapshot FenceTime::getSnapshot() const {
+    // Quick check without the lock.
+    nsecs_t signalTime = mSignalTime.load(std::memory_order_relaxed);
+    if (signalTime != Fence::SIGNAL_TIME_PENDING) {
+        return Snapshot(signalTime);
+    }
+
+    // Do the full check with the lock.
+    std::lock_guard<std::mutex> lock(mMutex);
+    signalTime = mSignalTime.load(std::memory_order_relaxed);
+    if (signalTime != Fence::SIGNAL_TIME_PENDING) {
+        return Snapshot(signalTime);
+    }
+    return Snapshot(mFence);
+}
+
+// ============================================================================
+// FenceTime::Snapshot
+// ============================================================================
+
+FenceTime::Snapshot::Snapshot(const sp<Fence>& srcFence)
+    : state(State::FENCE), fence(srcFence) {
+}
+
+FenceTime::Snapshot::Snapshot(nsecs_t srcSignalTime)
+    : state(State::SIGNAL_TIME), signalTime(srcSignalTime) {
+}
+
+size_t FenceTime::Snapshot::getFlattenedSize() const {
+    constexpr size_t min = sizeof(state);
+    switch (state) {
+        case State::EMPTY:
+            return min;
+        case State::FENCE:
+            return min + fence->getFlattenedSize();
+        case State::SIGNAL_TIME:
+            return min + sizeof(signalTime);
+    }
+    return 0;
+}
+
+size_t FenceTime::Snapshot::getFdCount() const {
+    return state == State::FENCE ? fence->getFdCount() : 0u;
+}
+
+status_t FenceTime::Snapshot::flatten(
+        void*& buffer, size_t& size, int*& fds, size_t& count) const {
+    if (size < getFlattenedSize()) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::write(buffer, size, state);
+    switch (state) {
+        case State::EMPTY:
+            return NO_ERROR;
+        case State::FENCE:
+            return fence->flatten(buffer, size, fds, count);
+        case State::SIGNAL_TIME:
+            FlattenableUtils::write(buffer, size, signalTime);
+            return NO_ERROR;
+    }
+
+    return NO_ERROR;
+}
+
+status_t FenceTime::Snapshot::unflatten(
+        void const*& buffer, size_t& size, int const*& fds, size_t& count) {
+    if (size < sizeof(state)) {
+        return NO_MEMORY;
+    }
+
+    FlattenableUtils::read(buffer, size, state);
+    switch (state) {
+        case State::EMPTY:
+            return NO_ERROR;
+        case State::FENCE:
+            fence = new Fence;
+            return fence->unflatten(buffer, size, fds, count);
+        case State::SIGNAL_TIME:
+            if (size < sizeof(signalTime)) {
+                return NO_MEMORY;
+            }
+            FlattenableUtils::read(buffer, size, signalTime);
+            return NO_ERROR;
+    }
+
+    return NO_ERROR;
+}
+
+// ============================================================================
+// FenceTimeline
+// ============================================================================
+void FenceTimeline::push(const std::shared_ptr<FenceTime>& fence) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    while (mQueue.size() >= MAX_ENTRIES) {
+        // This is a sanity check to make sure the queue doesn't grow unbounded.
+        // MAX_ENTRIES should be big enough not to trigger this path.
+        // In case this path is taken though, users of FenceTime must make sure
+        // not to rely solely on FenceTimeline to get the final timestamp and
+        // should eventually call Fence::getSignalTime on their own.
+        std::shared_ptr<FenceTime> front = mQueue.front().lock();
+        if (front) {
+            // Make a last ditch effort to get the signalTime here since
+            // we are removing it from the timeline.
+            front->getSignalTime();
+        }
+        mQueue.pop();
+    }
+    mQueue.push(fence);
+}
+
+void FenceTimeline::updateSignalTimes() {
+    while (!mQueue.empty()) {
+        std::lock_guard<std::mutex> lock(mMutex);
+        std::shared_ptr<FenceTime> fence = mQueue.front().lock();
+        if (!fence) {
+            // The shared_ptr no longer exists and no one cares about the
+            // timestamp anymore.
+            mQueue.pop();
+            continue;
+        } else if (fence->getSignalTime() != Fence::SIGNAL_TIME_PENDING) {
+            // The fence has signaled and we've removed the sp<Fence> ref.
+            mQueue.pop();
+            continue;
+        } else {
+            // The fence didn't signal yet. Break since the later ones
+            // shouldn't have signaled either.
+            break;
+        }
+    }
+}
+
+} // namespace android