diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index c6c3d29..0c4a752 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -56,6 +56,7 @@
         "StrongTypingTest.cpp",
         "VSyncDispatchTimerQueueTest.cpp",
         "VSyncDispatchRealtimeTest.cpp",
+        "VSyncPredictorTest.cpp",
         "mock/DisplayHardware/MockComposer.cpp",
         "mock/DisplayHardware/MockDisplay.cpp",
         "mock/DisplayHardware/MockPowerAdvisor.cpp",
diff --git a/services/surfaceflinger/tests/unittests/VSyncPredictorTest.cpp b/services/surfaceflinger/tests/unittests/VSyncPredictorTest.cpp
new file mode 100644
index 0000000..d0c8090
--- /dev/null
+++ b/services/surfaceflinger/tests/unittests/VSyncPredictorTest.cpp
@@ -0,0 +1,322 @@
+/*
+ * Copyright 2019 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/VSyncPredictor.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <algorithm>
+#include <chrono>
+#include <utility>
+
+using namespace testing;
+using namespace std::literals;
+
+namespace android::scheduler {
+
+MATCHER_P2(IsCloseTo, value, tolerance, "is within tolerance") {
+    return arg <= value + tolerance && value >= value - tolerance;
+}
+
+std::vector<nsecs_t> generateVsyncTimestamps(size_t count, nsecs_t period, nsecs_t bias) {
+    std::vector<nsecs_t> vsyncs(count);
+    std::generate(vsyncs.begin(), vsyncs.end(),
+                  [&, n = 0]() mutable { return n++ * period + bias; });
+    return vsyncs;
+}
+
+struct VSyncPredictorTest : testing::Test {
+    nsecs_t mNow = 0;
+    nsecs_t mPeriod = 1000;
+    static constexpr size_t kHistorySize = 10;
+    static constexpr size_t kMinimumSamplesForPrediction = 6;
+    static constexpr size_t kOutlierTolerancePercent = 25;
+    static constexpr nsecs_t mMaxRoundingError = 100;
+
+    VSyncPredictor tracker{mPeriod, kHistorySize, kMinimumSamplesForPrediction,
+                           kOutlierTolerancePercent};
+};
+
+TEST_F(VSyncPredictorTest, reportsAnticipatedPeriod) {
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+
+    EXPECT_THAT(slope, Eq(mPeriod));
+    EXPECT_THAT(intercept, Eq(0));
+
+    auto const changedPeriod = 2000;
+    tracker.setPeriod(changedPeriod);
+    std::tie(slope, intercept) = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, Eq(changedPeriod));
+    EXPECT_THAT(intercept, Eq(0));
+}
+
+TEST_F(VSyncPredictorTest, reportsSamplesNeededWhenHasNoDataPoints) {
+    for (auto i = 0u; i < kMinimumSamplesForPrediction; i++) {
+        EXPECT_TRUE(tracker.needsMoreSamples(mNow += mPeriod));
+        tracker.addVsyncTimestamp(mNow);
+    }
+    EXPECT_FALSE(tracker.needsMoreSamples(mNow));
+}
+
+TEST_F(VSyncPredictorTest, reportsSamplesNeededAfterExplicitRateChange) {
+    for (auto i = 0u; i < kMinimumSamplesForPrediction; i++) {
+        tracker.addVsyncTimestamp(mNow += mPeriod);
+    }
+    EXPECT_FALSE(tracker.needsMoreSamples(mNow));
+
+    auto const changedPeriod = mPeriod * 2;
+    tracker.setPeriod(changedPeriod);
+    EXPECT_TRUE(tracker.needsMoreSamples(mNow));
+
+    for (auto i = 0u; i < kMinimumSamplesForPrediction; i++) {
+        EXPECT_TRUE(tracker.needsMoreSamples(mNow += changedPeriod));
+        tracker.addVsyncTimestamp(mNow);
+    }
+    EXPECT_FALSE(tracker.needsMoreSamples(mNow));
+}
+
+TEST_F(VSyncPredictorTest, transitionsToModelledPointsAfterSynthetic) {
+    auto last = mNow;
+    auto const bias = 10;
+    for (auto i = 0u; i < kMinimumSamplesForPrediction; i++) {
+        EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow), Eq(last + mPeriod));
+        mNow += mPeriod - bias;
+        last = mNow;
+        tracker.addVsyncTimestamp(mNow);
+        mNow += bias;
+    }
+
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow), Eq(mNow + mPeriod - bias));
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow + 100), Eq(mNow + mPeriod - bias));
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow + 990), Eq(mNow + 2 * mPeriod - bias));
+}
+
+TEST_F(VSyncPredictorTest, uponNotifiedOfInaccuracyUsesSynthetic) {
+    auto const slightlyLessPeriod = mPeriod - 10;
+    auto const changedPeriod = mPeriod - 1;
+    for (auto i = 0u; i < kMinimumSamplesForPrediction; i++) {
+        tracker.addVsyncTimestamp(mNow += slightlyLessPeriod);
+    }
+
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow), Eq(mNow + slightlyLessPeriod));
+    tracker.setPeriod(changedPeriod);
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow), Eq(mNow + changedPeriod));
+}
+
+TEST_F(VSyncPredictorTest, adaptsToFenceTimelines_60hzHighVariance) {
+    // these are precomputed simulated 16.6s vsyncs with uniform distribution +/- 1.6ms error
+    std::vector<nsecs_t> const simulatedVsyncs{
+            15492949,  32325658,  49534984,  67496129,  84652891,
+            100332564, 117737004, 132125931, 149291099, 165199602,
+    };
+    auto constexpr idealPeriod = 16600000;
+    auto constexpr expectedPeriod = 16639242;
+    auto constexpr expectedIntercept = 1049341;
+
+    tracker.setPeriod(idealPeriod);
+    for (auto const& timestamp : simulatedVsyncs) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(expectedPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(expectedIntercept, mMaxRoundingError));
+}
+
+TEST_F(VSyncPredictorTest, adaptsToFenceTimelines_90hzLowVariance) {
+    // these are precomputed simulated 11.1 vsyncs with uniform distribution +/- 1ms error
+    std::vector<nsecs_t> const simulatedVsyncs{
+            11167047, 22603464, 32538479, 44938134, 56321268,
+            66730346, 78062637, 88171429, 99707843, 111397621,
+    };
+    auto idealPeriod = 11110000;
+    auto expectedPeriod = 11089413;
+    auto expectedIntercept = 94421;
+
+    tracker.setPeriod(idealPeriod);
+    for (auto const& timestamp : simulatedVsyncs) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(expectedPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(expectedIntercept, mMaxRoundingError));
+}
+
+TEST_F(VSyncPredictorTest, adaptsToFenceTimelinesDiscontinuous_22hzLowVariance) {
+    // these are 11.1s vsyncs with low variance, randomly computed, between -1 and 1ms
+    std::vector<nsecs_t> const simulatedVsyncs{
+            45259463,   // 0
+            91511026,   // 1
+            136307650,  // 2
+            1864501714, // 40
+            1908641034, // 41
+            1955278544, // 42
+            4590180096, // 100
+            4681594994, // 102
+            5499224734, // 120
+            5591378272, // 122
+    };
+    auto idealPeriod = 45454545;
+    auto expectedPeriod = 45450152;
+    auto expectedIntercept = 469647;
+
+    tracker.setPeriod(idealPeriod);
+    for (auto const& timestamp : simulatedVsyncs) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(expectedPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(expectedIntercept, mMaxRoundingError));
+}
+
+TEST_F(VSyncPredictorTest, againstOutliersDiscontinuous_500hzLowVariance) {
+    std::vector<nsecs_t> const simulatedVsyncs{
+            1992548,    // 0
+            4078038,    // 1
+            6165794,    // 2
+            7958171,    // 3
+            10193537,   // 4
+            2401840200, // 1200
+            2403000000, // an outlier that should be excluded (1201 and a half)
+            2405803629, // 1202
+            2408028599, // 1203
+            2410121051, // 1204
+    };
+    auto idealPeriod = 2000000;
+    auto expectedPeriod = 1999892;
+    auto expectedIntercept = 175409;
+
+    tracker.setPeriod(idealPeriod);
+    for (auto const& timestamp : simulatedVsyncs) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(expectedPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(expectedIntercept, mMaxRoundingError));
+}
+
+TEST_F(VSyncPredictorTest, handlesVsyncChange) {
+    auto const fastPeriod = 100;
+    auto const fastTimeBase = 100;
+    auto const slowPeriod = 400;
+    auto const slowTimeBase = 800;
+    auto const simulatedVsyncsFast =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction, fastPeriod, fastTimeBase);
+    auto const simulatedVsyncsSlow =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction, slowPeriod, slowTimeBase);
+
+    tracker.setPeriod(fastPeriod);
+    for (auto const& timestamp : simulatedVsyncsFast) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+
+    auto const mMaxRoundingError = 100;
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(fastPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(0, mMaxRoundingError));
+
+    tracker.setPeriod(slowPeriod);
+    for (auto const& timestamp : simulatedVsyncsSlow) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    std::tie(slope, intercept) = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, IsCloseTo(slowPeriod, mMaxRoundingError));
+    EXPECT_THAT(intercept, IsCloseTo(0, mMaxRoundingError));
+}
+
+TEST_F(VSyncPredictorTest, willBeAccurateUsingPriorResultsForRate) {
+    auto const fastPeriod = 101000;
+    auto const fastTimeBase = fastPeriod - 500;
+    auto const fastPeriod2 = 99000;
+
+    auto const slowPeriod = 400000;
+    auto const slowTimeBase = 800000 - 201;
+    auto const simulatedVsyncsFast =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction, fastPeriod, fastTimeBase);
+    auto const simulatedVsyncsSlow =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction, slowPeriod, slowTimeBase);
+    auto const simulatedVsyncsFast2 =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction, fastPeriod2, fastTimeBase);
+
+    auto idealPeriod = 100000;
+    tracker.setPeriod(idealPeriod);
+    for (auto const& timestamp : simulatedVsyncsFast) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    auto [slope, intercept] = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, Eq(fastPeriod));
+    EXPECT_THAT(intercept, Eq(0));
+
+    tracker.setPeriod(slowPeriod);
+    for (auto const& timestamp : simulatedVsyncsSlow) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+
+    // we had a model for 100ns mPeriod before, use that until the new samples are
+    // sufficiently built up
+    tracker.setPeriod(idealPeriod);
+    std::tie(slope, intercept) = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, Eq(fastPeriod));
+    EXPECT_THAT(intercept, Eq(0));
+
+    for (auto const& timestamp : simulatedVsyncsFast2) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    std::tie(slope, intercept) = tracker.getVSyncPredictionModel();
+    EXPECT_THAT(slope, Eq(fastPeriod2));
+    EXPECT_THAT(intercept, Eq(0));
+}
+
+TEST_F(VSyncPredictorTest, willBecomeInaccurateAfterA_longTimeWithNoSamples) {
+    auto const simulatedVsyncs = generateVsyncTimestamps(kMinimumSamplesForPrediction, mPeriod, 0);
+
+    for (auto const& timestamp : simulatedVsyncs) {
+        tracker.addVsyncTimestamp(timestamp);
+    }
+    auto const mNow = *simulatedVsyncs.rbegin();
+    EXPECT_FALSE(tracker.needsMoreSamples(mNow));
+
+    // TODO: would be better to decay this as a result of the variance of the samples
+    static auto constexpr aLongTimeOut = 1000000000;
+    EXPECT_TRUE(tracker.needsMoreSamples(mNow + aLongTimeOut));
+}
+
+TEST_F(VSyncPredictorTest, idealModelPredictionsBeforeRegressionModelIsBuilt) {
+    auto const simulatedVsyncs =
+            generateVsyncTimestamps(kMinimumSamplesForPrediction + 1, mPeriod, 0);
+    nsecs_t const mNow = 0;
+    EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(mNow), Eq(mPeriod));
+
+    nsecs_t const aBitOfTime = 422;
+
+    for (auto i = 0; i < kMinimumSamplesForPrediction; i++) {
+        tracker.addVsyncTimestamp(simulatedVsyncs[i]);
+        EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(simulatedVsyncs[i] + aBitOfTime),
+                    Eq(mPeriod + simulatedVsyncs[i]));
+    }
+
+    for (auto i = kMinimumSamplesForPrediction; i < simulatedVsyncs.size(); i++) {
+        tracker.addVsyncTimestamp(simulatedVsyncs[i]);
+        EXPECT_THAT(tracker.nextAnticipatedVSyncTimeFrom(simulatedVsyncs[i] + aBitOfTime),
+                    Eq(mPeriod + simulatedVsyncs[i]));
+    }
+}
+
+} // namespace android::scheduler