Merge changes from topic "android_dynamic_performance_framework" into sc-dev

* changes:
  Integrate HWUI with PerformanceHintManager
  ADPF: Add HintManagerService
  ADPF: PerformanceHintManager API implementation

29 files changed, 1701 insertions, 52 deletions

diff --git a/core/api/current.txt b/core/api/current.txt
index 1f7da095a1a7..1ac6d946f054 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -10644,6 +10644,7 @@ package android.content {
     field public static final String NOTIFICATION_SERVICE = "notification";
     field public static final String NSD_SERVICE = "servicediscovery";
     field public static final String PEOPLE_SERVICE = "people";
+    field public static final String PERFORMANCE_HINT_SERVICE = "performance_hint";
     field public static final String POWER_SERVICE = "power";
     field public static final String PRINT_SERVICE = "print";
     field public static final int RECEIVER_VISIBLE_TO_INSTANT_APPS = 1; // 0x1
@@ -31559,6 +31560,17 @@ package android.os {
     field public static final int PATTERN_SUFFIX = 4; // 0x4
   }
 
+  public final class PerformanceHintManager {
+    method @Nullable public android.os.PerformanceHintManager.Session createHintSession(@NonNull int[], long);
+    method public long getPreferredUpdateRateNanos();
+  }
+
+  public static class PerformanceHintManager.Session implements java.io.Closeable {
+    method public void close();
+    method public void reportActualWorkDuration(long);
+    method public void updateTargetWorkDuration(long);
+  }
+
   public final class PersistableBundle extends android.os.BaseBundle implements java.lang.Cloneable android.os.Parcelable {
     ctor public PersistableBundle();
     ctor public PersistableBundle(int);
diff --git a/core/java/android/app/SystemServiceRegistry.java b/core/java/android/app/SystemServiceRegistry.java
index 47a9fbb5fe4a..91dad2a1f13c 100644
--- a/core/java/android/app/SystemServiceRegistry.java
+++ b/core/java/android/app/SystemServiceRegistry.java
@@ -158,12 +158,14 @@ import android.os.IBatteryPropertiesRegistrar;
 import android.os.IBinder;
 import android.os.IDumpstate;
 import android.os.IHardwarePropertiesManager;
+import android.os.IHintManager;
 import android.os.IPowerManager;
 import android.os.IRecoverySystem;
 import android.os.ISystemUpdateManager;
 import android.os.IThermalService;
 import android.os.IUserManager;
 import android.os.IncidentManager;
+import android.os.PerformanceHintManager;
 import android.os.PowerManager;
 import android.os.RecoverySystem;
 import android.os.ServiceManager;
@@ -592,6 +594,17 @@ public final class SystemServiceRegistry {
                         ctx.mMainThread.getHandler());
             }});
 
+        registerService(Context.PERFORMANCE_HINT_SERVICE, PerformanceHintManager.class,
+                new CachedServiceFetcher<PerformanceHintManager>() {
+            @Override
+            public PerformanceHintManager createService(ContextImpl ctx)
+                    throws ServiceNotFoundException {
+                IBinder hintBinder = ServiceManager.getServiceOrThrow(
+                        Context.PERFORMANCE_HINT_SERVICE);
+                IHintManager hintService = IHintManager.Stub.asInterface(hintBinder);
+                return new PerformanceHintManager(hintService);
+            }});
+
         registerService(Context.RECOVERY_SERVICE, RecoverySystem.class,
                 new CachedServiceFetcher<RecoverySystem>() {
             @Override
diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index 1226858bba71..5d66cdf880b8 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -5226,6 +5226,14 @@ public abstract class Context {
 
     /**
      * Use with {@link #getSystemService(String)} to retrieve a
+     * {@link android.os.PerformanceHintManager} for accessing the performance hinting service.
+     *
+     * @see #getSystemService(String)
+     */
+    public static final String PERFORMANCE_HINT_SERVICE = "performance_hint";
+
+    /**
+     * Use with {@link #getSystemService(String)} to retrieve a
      * {@link android.content.pm.ShortcutManager} for accessing the launcher shortcut service.
      *
      * @see #getSystemService(String)
diff --git a/core/java/android/os/IHintManager.aidl b/core/java/android/os/IHintManager.aidl
new file mode 100644
index 000000000000..661b95affaf3
--- /dev/null
+++ b/core/java/android/os/IHintManager.aidl
@@ -0,0 +1,33 @@
+/*
+ *
+ * Copyright 2021, 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.
+ */
+
+package android.os;
+
+import android.os.IHintSession;
+
+/** {@hide} */
+interface IHintManager {
+    /**
+     * Creates a {@link Session} for the given set of threads and associates to a binder token.
+     */
+   IHintSession createHintSession(in IBinder token, in int[] tids, long durationNanos);
+
+    /**
+     * Get preferred rate limit in nano second.
+     */
+   long getHintSessionPreferredRate();
+}
diff --git a/core/java/android/os/IHintSession.aidl b/core/java/android/os/IHintSession.aidl
new file mode 100644
index 000000000000..09bc4cc4eb7e
--- /dev/null
+++ b/core/java/android/os/IHintSession.aidl
@@ -0,0 +1,25 @@
+/*
+ *
+ * Copyright 2021, 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.
+ */
+
+package android.os;
+
+/** {@hide} */
+oneway interface IHintSession {
+    void updateTargetWorkDuration(long targetDurationNanos);
+    void reportActualWorkDuration(in long[] actualDurationNanos, in long[] timeStampNanos);
+    void close();
+}
diff --git a/core/java/android/os/PerformanceHintManager.java b/core/java/android/os/PerformanceHintManager.java
new file mode 100644
index 000000000000..6791844a2a00
--- /dev/null
+++ b/core/java/android/os/PerformanceHintManager.java
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+package android.os;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.annotation.SystemService;
+import android.content.Context;
+
+import com.android.internal.util.Preconditions;
+
+import java.io.Closeable;
+import java.util.ArrayList;
+
+/** The PerformanceHintManager allows apps to send performance hint to system. */
+@SystemService(Context.PERFORMANCE_HINT_SERVICE)
+public final class PerformanceHintManager {
+    private static final String TAG = "PerformanceHintManager";
+    private final IHintManager mService;
+    // HAL preferred update rate
+    private final long mPreferredRate;
+
+    /** @hide */
+    public PerformanceHintManager(IHintManager service) {
+        mService = service;
+        try {
+            mPreferredRate = mService.getHintSessionPreferredRate();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Creates a {@link Session} for the given set of threads and sets their initial target work
+     * duration.
+     *
+     * @param tids The list of threads to be associated with this session. They must be part of
+     *     this process' thread group.
+     * @param initialTargetWorkDurationNanos The desired duration in nanoseconds for the new
+     *     session.
+     * @return the new session if it is supported on this device, null if hint session is not
+     *     supported on this device.
+     */
+    @Nullable
+    public Session createHintSession(@NonNull int[] tids, long initialTargetWorkDurationNanos) {
+        try {
+            IBinder token = new Binder();
+            IHintSession session = mService.createHintSession(token, tids,
+                    initialTargetWorkDurationNanos);
+            if (session == null) return null;
+            return new Session(session, sNanoClock, mPreferredRate,
+                    initialTargetWorkDurationNanos);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Get preferred update rate information for this device.
+     *
+     * @return the preferred update rate supported by device software.
+     */
+    public long getPreferredUpdateRateNanos() {
+        return mPreferredRate;
+    }
+
+    /**
+     * A Session represents a group of threads with an inter-related workload such that hints for
+     * their performance should be considered as a unit. The threads in a given session should be
+     * long-life and not created or destroyed dynamically.
+     *
+     * <p>Each session is expected to have a periodic workload with a target duration for each
+     * cycle. The cycle duration is likely greater than the target work duration to allow other
+     * parts of the pipeline to run within the available budget. For example, a renderer thread may
+     * work at 60hz in order to produce frames at the display's frame but have a target work
+     * duration of only 6ms.</p>
+     *
+     * <p>Any call in this class will change its internal data, so you must do your own thread
+     * safety to protect from racing.</p>
+     *
+     * <p>Note that the target work duration can be {@link #updateTargetWorkDuration(long) updated}
+     * if workloads change.</p>
+     *
+     * <p>After each cycle of work, the client is expected to
+     * {@link #reportActualWorkDuration(long) report} the actual time taken to complete.</p>
+     *
+     * <p>All timings should be in {@link SystemClock#elapsedRealtimeNanos()}.</p>
+     */
+    public static class Session implements Closeable {
+        private final IHintSession mSession;
+        private final NanoClock mElapsedRealtimeClock;
+        // Target duration for choosing update rate
+        private long mTargetDurationInNanos;
+        // HAL preferred update rate
+        private long mPreferredRate;
+        // Last update timestamp
+        private long mLastUpdateTimeStamp = -1L;
+        // Cached samples
+        private final ArrayList<Long> mActualDurationNanos;
+        private final ArrayList<Long> mTimeStampNanos;
+
+        /** @hide */
+        public Session(IHintSession session, NanoClock elapsedRealtimeClock, long preferredRate,
+                long durationNanos) {
+            mSession = session;
+            mElapsedRealtimeClock = elapsedRealtimeClock;
+            mTargetDurationInNanos = durationNanos;
+            mPreferredRate = preferredRate;
+            mActualDurationNanos = new ArrayList<Long>();
+            mTimeStampNanos = new ArrayList<Long>();
+            mLastUpdateTimeStamp = mElapsedRealtimeClock.nanos();
+        }
+
+        /**
+         * Updates this session's target duration for each cycle of work.
+         *
+         * @param targetDurationNanos the new desired duration in nanoseconds
+         */
+        public void updateTargetWorkDuration(long targetDurationNanos) {
+            Preconditions.checkArgumentPositive(targetDurationNanos, "the hint target duration"
+                    + " should be positive.");
+            try {
+                mSession.updateTargetWorkDuration(targetDurationNanos);
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+            mTargetDurationInNanos = targetDurationNanos;
+            /**
+             * Most of the workload is target_duration dependent, so now clear the cached samples
+             * as they are most likely obsolete.
+             */
+            mActualDurationNanos.clear();
+            mTimeStampNanos.clear();
+            mLastUpdateTimeStamp = mElapsedRealtimeClock.nanos();
+        }
+
+        /**
+         * Reports the actual duration for the last cycle of work.
+         *
+         * <p>The system will attempt to adjust the core placement of the threads within the thread
+         * group and/or the frequency of the core on which they are run to bring the actual duration
+         * close to the target duration.</p>
+         *
+         * @param actualDurationNanos how long the thread group took to complete its last task in
+         *     nanoseconds
+         */
+        public void reportActualWorkDuration(long actualDurationNanos) {
+            Preconditions.checkArgumentPositive(actualDurationNanos, "the actual duration should"
+                    + " be positive.");
+            final long now = mElapsedRealtimeClock.nanos();
+            mActualDurationNanos.add(actualDurationNanos);
+            mTimeStampNanos.add(now);
+
+            /**
+             * Use current sample to determine the rate limit. We can pick a shorter rate limit
+             * if any sample underperformed, however, it could be the lower level system is slow
+             * to react. So here we explicitly choose the rate limit with the latest sample.
+             */
+            long rateLimit =
+                    actualDurationNanos > mTargetDurationInNanos ? mPreferredRate
+                            : 10 * mPreferredRate;
+
+            if (now - mLastUpdateTimeStamp <= rateLimit) {
+                return;
+            }
+            Preconditions.checkState(mActualDurationNanos.size() == mTimeStampNanos.size());
+            final int size = mActualDurationNanos.size();
+            long[] actualDurationArray = new long[size];
+            long[] timeStampArray = new long[size];
+            for (int i = 0; i < size; i++) {
+                actualDurationArray[i] = mActualDurationNanos.get(i);
+                timeStampArray[i] = mTimeStampNanos.get(i);
+            }
+            try {
+                mSession.reportActualWorkDuration(actualDurationArray, timeStampArray);
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+            mActualDurationNanos.clear();
+            mTimeStampNanos.clear();
+            mLastUpdateTimeStamp = now;
+        }
+
+        /**
+         * Ends the current hint session.
+         *
+         * <p>Once called, you should not call anything else on this object.</p>
+         */
+        public void close() {
+            try {
+                mSession.close();
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
+     * The interface is to make the FakeClock for testing.
+     * @hide
+     */
+    public interface NanoClock {
+        /** Gets the current nanosecond instant of the clock. */
+        long nanos();
+    }
+
+    private static final NanoClock sNanoClock = new NanoClock() {
+        public long nanos() {
+            return SystemClock.elapsedRealtimeNanos();
+        }
+    };
+}
diff --git a/core/java/android/view/Choreographer.java b/core/java/android/view/Choreographer.java
index 5c65c659e576..7b3a8a64fc37 100644
--- a/core/java/android/view/Choreographer.java
+++ b/core/java/android/view/Choreographer.java
@@ -737,7 +737,7 @@ public final class Choreographer {
             }
 
             mFrameInfo.setVsync(intendedFrameTimeNanos, frameTimeNanos, vsyncEventData.id,
-                    vsyncEventData.frameDeadline);
+                    vsyncEventData.frameDeadline, startNanos);
             mFrameScheduled = false;
             mLastFrameTimeNanos = frameTimeNanos;
             mLastVsyncEventData = vsyncEventData;
diff --git a/core/java/android/view/FrameMetrics.java b/core/java/android/view/FrameMetrics.java
index eb49e52d5050..9cdf91a55c39 100644
--- a/core/java/android/view/FrameMetrics.java
+++ b/core/java/android/view/FrameMetrics.java
@@ -242,18 +242,19 @@ public final class FrameMetrics {
         int PERFORM_TRAVERSALS_START = 7;
         int DRAW_START = 8;
         int FRAME_DEADLINE = 9;
-        int SYNC_QUEUED = 10;
-        int SYNC_START = 11;
-        int ISSUE_DRAW_COMMANDS_START = 12;
-        int SWAP_BUFFERS = 13;
-        int FRAME_COMPLETED = 14;
-        int DEQUEUE_BUFFER_DURATION = 15;
-        int QUEUE_BUFFER_DURATION = 16;
-        int GPU_COMPLETED = 17;
-        int SWAP_BUFFERS_COMPLETED = 18;
-        int DISPLAY_PRESENT_TIME = 19;
+        int FRAME_START_TIME = 10;
+        int SYNC_QUEUED = 11;
+        int SYNC_START = 12;
+        int ISSUE_DRAW_COMMANDS_START = 13;
+        int SWAP_BUFFERS = 14;
+        int FRAME_COMPLETED = 15;
+        int DEQUEUE_BUFFER_DURATION = 16;
+        int QUEUE_BUFFER_DURATION = 17;
+        int GPU_COMPLETED = 18;
+        int SWAP_BUFFERS_COMPLETED = 19;
+        int DISPLAY_PRESENT_TIME = 20;
 
-        int FRAME_STATS_COUNT = 20; // must always be last and in sync with
+        int FRAME_STATS_COUNT = 21; // must always be last and in sync with
                                     // FrameInfoIndex::NumIndexes in libs/hwui/FrameInfo.h
     }
 
diff --git a/core/tests/coretests/src/android/os/PerformanceHintManagerTest.java b/core/tests/coretests/src/android/os/PerformanceHintManagerTest.java
new file mode 100644
index 000000000000..7dea82d7ee54
--- /dev/null
+++ b/core/tests/coretests/src/android/os/PerformanceHintManagerTest.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+package android.os;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeNotNull;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.os.PerformanceHintManager.Session;
+
+import androidx.test.InstrumentationRegistry;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+@RunWith(AndroidJUnit4.class)
+public class PerformanceHintManagerTest {
+    private static final long RATE_1000 = 1000L;
+    private static final long TARGET_166 = 166L;
+    private static final long DEFAULT_TARGET_NS = 16666666L;
+    private PerformanceHintManager mPerformanceHintManager;
+
+    @Mock
+    private IHintSession mIHintSessionMock;
+
+    @Before
+    public void setUp() {
+        mPerformanceHintManager =
+                InstrumentationRegistry.getInstrumentation().getContext().getSystemService(
+                        PerformanceHintManager.class);
+        MockitoAnnotations.initMocks(this);
+    }
+
+    private Session createSession() {
+        return mPerformanceHintManager.createHintSession(
+                new int[]{Process.myPid()}, DEFAULT_TARGET_NS);
+    }
+
+    @Test
+    public void testCreateHintSession() {
+        Session a = createSession();
+        Session b = createSession();
+        if (a == null) {
+            assertNull(b);
+        } else {
+            assertNotEquals(a, b);
+        }
+    }
+
+    @Test
+    public void testGetPreferredUpdateRateNanos() {
+        if (createSession() != null) {
+            assertTrue(mPerformanceHintManager.getPreferredUpdateRateNanos() > 0);
+        } else {
+            assertEquals(-1, mPerformanceHintManager.getPreferredUpdateRateNanos());
+        }
+    }
+
+    @Test
+    public void testUpdateTargetWorkDuration() {
+        Session s = createSession();
+        assumeNotNull(s);
+        s.updateTargetWorkDuration(100);
+    }
+
+    @Test
+    public void testUpdateTargetWorkDurationWithNegativeDuration() {
+        Session s = createSession();
+        assumeNotNull(s);
+        assertThrows(IllegalArgumentException.class, () -> {
+            s.updateTargetWorkDuration(-1);
+        });
+    }
+
+    @Test
+    public void testReportActualWorkDuration() {
+        Session s = createSession();
+        assumeNotNull(s);
+        s.updateTargetWorkDuration(100);
+        s.reportActualWorkDuration(1);
+        s.reportActualWorkDuration(100);
+        s.reportActualWorkDuration(1000);
+    }
+
+    @Test
+    public void testReportActualWorkDurationWithIllegalArgument() {
+        Session s = createSession();
+        assumeNotNull(s);
+        s.updateTargetWorkDuration(100);
+        assertThrows(IllegalArgumentException.class, () -> {
+            s.reportActualWorkDuration(-1);
+        });
+    }
+
+    @Test
+    public void testRateLimitWithDurationFastEnough() throws Exception {
+        FakeClock fakeClock = new FakeClock();
+        Session s = new Session(mIHintSessionMock, fakeClock, RATE_1000, TARGET_166);
+
+        reset(mIHintSessionMock);
+        fakeClock.setNow(0);
+        s.updateTargetWorkDuration(TARGET_166);
+
+        s.reportActualWorkDuration(TARGET_166 - 1);
+        s.reportActualWorkDuration(TARGET_166);
+        // we should not see update as the rate should be 10X for over-perform case.
+        verify(mIHintSessionMock, never()).reportActualWorkDuration(any(), any());
+        fakeClock.incrementClock(10 * RATE_1000);
+        s.reportActualWorkDuration(TARGET_166);
+        verify(mIHintSessionMock, never()).reportActualWorkDuration(any(), any());
+        fakeClock.incrementClock(1);
+        s.reportActualWorkDuration(TARGET_166);
+        // we should see update after rate limit
+        verify(mIHintSessionMock, times(1)).reportActualWorkDuration(
+                eq(new long[] {TARGET_166 - 1, TARGET_166, TARGET_166, TARGET_166}),
+                eq(new long[] {0, 0, 10 * RATE_1000, 10 * RATE_1000 + 1}));
+
+        reset(mIHintSessionMock);
+        s.reportActualWorkDuration(TARGET_166);
+        s.reportActualWorkDuration(TARGET_166 - 1);
+        s.reportActualWorkDuration(TARGET_166 - 2);
+        // we should not see update as the rate should be 10X for over-perform case.
+        verify(mIHintSessionMock, never()).reportActualWorkDuration(any(), any());
+        fakeClock.incrementClock(10 * RATE_1000 + 1);
+        s.reportActualWorkDuration(TARGET_166);
+        s.reportActualWorkDuration(TARGET_166 - 1);
+        // we should see update now
+        verify(mIHintSessionMock, times(1)).reportActualWorkDuration(
+                eq(new long[] {TARGET_166, TARGET_166 - 1, TARGET_166 - 2, TARGET_166}),
+                eq(new long[] {10 * RATE_1000 + 1, 10 * RATE_1000 + 1, 10 * RATE_1000 + 1,
+                    (10 * RATE_1000 + 1) * 2}));
+    }
+
+    @Test
+    public void testRateLimitWithDurationTooSlow() throws Exception {
+        FakeClock fakeClock = new FakeClock();
+        Session s = new Session(mIHintSessionMock, fakeClock, RATE_1000, TARGET_166);
+
+        reset(mIHintSessionMock);
+        fakeClock.setNow(0);
+        s.updateTargetWorkDuration(TARGET_166);
+
+        verify(mIHintSessionMock, times(1)).updateTargetWorkDuration(eq(TARGET_166));
+        // shouldn't update before rate limit
+        s.reportActualWorkDuration(TARGET_166 + 1);
+        verify(mIHintSessionMock, never()).reportActualWorkDuration(any(), any());
+
+        // shouldn't update when the time is exactly at rate limit
+        fakeClock.incrementClock(RATE_1000);
+        s.reportActualWorkDuration(TARGET_166 + 1);
+        verify(mIHintSessionMock, never()).reportActualWorkDuration(any(), any());
+
+        // should be ready for sending hint
+        fakeClock.incrementClock(1);
+        s.reportActualWorkDuration(TARGET_166 + 1);
+        verify(mIHintSessionMock, times(1)).reportActualWorkDuration(
+                eq(new long[] {TARGET_166 + 1, TARGET_166 + 1, TARGET_166 + 1}),
+                eq(new long[] {0 , RATE_1000, RATE_1000 + 1}));
+    }
+
+    @Test
+    public void testCloseHintSession() {
+        Session s = createSession();
+        assumeNotNull(s);
+        s.close();
+    }
+
+    private static class FakeClock implements PerformanceHintManager.NanoClock {
+        private long mCurrentTime = 0L;
+
+        @Override
+        public long nanos() {
+            return mCurrentTime;
+        }
+
+        public void setNow(long nanos) {
+            mCurrentTime = nanos;
+        }
+
+        public void incrementClock(long nanos) {
+            mCurrentTime += nanos;
+        }
+    }
+}
diff --git a/graphics/java/android/graphics/FrameInfo.java b/graphics/java/android/graphics/FrameInfo.java
index 189be53a397f..786c03ba5150 100644
--- a/graphics/java/android/graphics/FrameInfo.java
+++ b/graphics/java/android/graphics/FrameInfo.java
@@ -87,18 +87,22 @@ public final class FrameInfo {
     // When the frame needs to be ready by
     public static final int FRAME_DEADLINE = 9;
 
+    // When frame actually started.
+    public static final int FRAME_START_TIME = 10;
+
     // Must be the last one
     // This value must be in sync with `UI_THREAD_FRAME_INFO_SIZE` in FrameInfo.h
-    private static final int FRAME_INFO_SIZE = FRAME_DEADLINE + 1;
+    private static final int FRAME_INFO_SIZE = FRAME_START_TIME + 1;
 
     /** checkstyle */
     public void setVsync(long intendedVsync, long usedVsync, long frameTimelineVsyncId,
-            long frameDeadline) {
+            long frameDeadline, long frameStartTime) {
         frameInfo[FRAME_TIMELINE_VSYNC_ID] = frameTimelineVsyncId;
         frameInfo[INTENDED_VSYNC] = intendedVsync;
         frameInfo[VSYNC] = usedVsync;
         frameInfo[FLAGS] = 0;
         frameInfo[FRAME_DEADLINE] = frameDeadline;
+        frameInfo[FRAME_START_TIME] = frameStartTime;
     }
 
     /** checkstyle */
diff --git a/graphics/java/android/graphics/HardwareRenderer.java b/graphics/java/android/graphics/HardwareRenderer.java
index 88cf96a9eb4e..7589435fc3b7 100644
--- a/graphics/java/android/graphics/HardwareRenderer.java
+++ b/graphics/java/android/graphics/HardwareRenderer.java
@@ -28,6 +28,7 @@ import android.content.res.Configuration;
 import android.hardware.display.DisplayManager;
 import android.os.IBinder;
 import android.os.ParcelFileDescriptor;
+import android.os.PerformanceHintManager;
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.util.Log;
@@ -165,7 +166,7 @@ public class HardwareRenderer {
      * to opaque with no light source configured.
      */
     public HardwareRenderer() {
-        ProcessInitializer.sInstance.initDisplayInfo();
+        ProcessInitializer.sInstance.initUsingContext();
         mRootNode = RenderNode.adopt(nCreateRootRenderNode());
         mRootNode.setClipToBounds(false);
         mNativeProxy = nCreateProxy(!mOpaque, mRootNode.mNativeRenderNode);
@@ -365,7 +366,8 @@ public class HardwareRenderer {
          */
         public @NonNull FrameRenderRequest setVsyncTime(long vsyncTime) {
             // TODO(b/168552873): populate vsync Id once available to Choreographer public API
-            mFrameInfo.setVsync(vsyncTime, vsyncTime, FrameInfo.INVALID_VSYNC_ID, Long.MAX_VALUE);
+            mFrameInfo.setVsync(vsyncTime, vsyncTime, FrameInfo.INVALID_VSYNC_ID, Long.MAX_VALUE,
+                    vsyncTime);
             mFrameInfo.addFlags(FrameInfo.FLAG_SURFACE_CANVAS);
             return this;
         }
@@ -835,6 +837,36 @@ public class HardwareRenderer {
         callback.onPictureCaptured(picture);
     }
 
+    /** called by native */
+    static PerformanceHintManager.Session createHintSession(int[] tids) {
+        PerformanceHintManager performanceHintManager =
+                ProcessInitializer.sInstance.getHintManager();
+        if (performanceHintManager == null) {
+            return null;
+        }
+        // Native code will always set a target duration before reporting actual durations.
+        // So this is just a placeholder value that's never used.
+        long targetDurationNanos = 16666667;
+        return performanceHintManager.createHintSession(tids, targetDurationNanos);
+    }
+
+    /** called by native */
+    static void updateTargetWorkDuration(PerformanceHintManager.Session session,
+            long targetDurationNanos) {
+        session.updateTargetWorkDuration(targetDurationNanos);
+    }
+
+    /** called by native */
+    static void reportActualWorkDuration(PerformanceHintManager.Session session,
+            long actualDurationNanos) {
+        session.reportActualWorkDuration(actualDurationNanos);
+    }
+
+    /** called by native */
+    static void closeHintSession(PerformanceHintManager.Session session) {
+        session.close();
+    }
+
     /**
      * Interface used to receive callbacks when a frame is being drawn.
      *
@@ -1071,6 +1103,7 @@ public class HardwareRenderer {
         private boolean mIsolated = false;
         private Context mContext;
         private String mPackageName;
+        private PerformanceHintManager mPerformanceHintManager;
         private IGraphicsStats mGraphicsStatsService;
         private IGraphicsStatsCallback mGraphicsStatsCallback = new IGraphicsStatsCallback.Stub() {
             @Override
@@ -1082,6 +1115,10 @@ public class HardwareRenderer {
         private ProcessInitializer() {
         }
 
+        synchronized PerformanceHintManager getHintManager() {
+            return mPerformanceHintManager;
+        }
+
         synchronized void setPackageName(String name) {
             if (mInitialized) return;
             mPackageName = name;
@@ -1127,15 +1164,23 @@ public class HardwareRenderer {
             }
         }
 
-        synchronized void initDisplayInfo() {
-            if (mDisplayInitialized) return;
+        synchronized void initUsingContext() {
             if (mContext == null) return;
 
-            // If we're in an isolated sandbox mode then we shouldn't try to communicate with DMS
+            initDisplayInfo();
+
+            // HintManager and HintSession are designed to be accessible from isoalted processes
+            // so not checking for isolated process here.
+            initHintSession();
+
+            // Defensively clear out the context in case we were passed a context that can leak
+            // if we live longer than it, e.g. an activity context.
+            mContext = null;
+        }
+
+        private void initDisplayInfo() {
+            if (mDisplayInitialized) return;
             if (mIsolated) {
-                // Defensively clear out the context in case we were passed a context that can leak
-                // if we live longer than it, e.g. an activity context.
-                mContext = null;
                 mDisplayInitialized = true;
                 return;
             }
@@ -1167,11 +1212,14 @@ public class HardwareRenderer {
                     display.getRefreshRate(), wideColorDataspace.mNativeDataspace,
                     display.getAppVsyncOffsetNanos(), display.getPresentationDeadlineNanos());
 
-            // Defensively clear out the context
-            mContext = null;
             mDisplayInitialized = true;
         }
 
+        private void initHintSession() {
+            if (mContext == null) return;
+            mPerformanceHintManager = mContext.getSystemService(PerformanceHintManager.class);
+        }
+
         private void rotateBuffer() {
             nRotateProcessStatsBuffer();
             requestBuffer();
diff --git a/libs/hwui/FrameInfo.cpp b/libs/hwui/FrameInfo.cpp
index 2448cc904104..51fbf363f51c 100644
--- a/libs/hwui/FrameInfo.cpp
+++ b/libs/hwui/FrameInfo.cpp
@@ -21,29 +21,16 @@ namespace android {
 namespace uirenderer {
 
 const std::array FrameInfoNames{
-        "Flags",
-        "FrameTimelineVsyncId",
-        "IntendedVsync",
-        "Vsync",
-        "InputEventId",
-        "HandleInputStart",
-        "AnimationStart",
-        "PerformTraversalsStart",
-        "DrawStart",
-        "FrameDeadline",
-        "SyncQueued",
-        "SyncStart",
-        "IssueDrawCommandsStart",
-        "SwapBuffers",
-        "FrameCompleted",
-        "DequeueBufferDuration",
-        "QueueBufferDuration",
-        "GpuCompleted",
-        "SwapBuffersCompleted",
-        "DisplayPresentTime",
+        "Flags",          "FrameTimelineVsyncId",   "IntendedVsync",
+        "Vsync",          "InputEventId",           "HandleInputStart",
+        "AnimationStart", "PerformTraversalsStart", "DrawStart",
+        "FrameDeadline",  "FrameStartTime",         "SyncQueued",
+        "SyncStart",      "IssueDrawCommandsStart", "SwapBuffers",
+        "FrameCompleted", "DequeueBufferDuration",  "QueueBufferDuration",
+        "GpuCompleted",   "SwapBuffersCompleted",   "DisplayPresentTime",
 };
 
-static_assert(static_cast<int>(FrameInfoIndex::NumIndexes) == 20,
+static_assert(static_cast<int>(FrameInfoIndex::NumIndexes) == 21,
               "Must update value in FrameMetrics.java#FRAME_STATS_COUNT (and here)");
 
 void FrameInfo::importUiThreadInfo(int64_t* info) {
diff --git a/libs/hwui/FrameInfo.h b/libs/hwui/FrameInfo.h
index e9b2f4a9bb3b..62ac4ca5fdad 100644
--- a/libs/hwui/FrameInfo.h
+++ b/libs/hwui/FrameInfo.h
@@ -28,7 +28,7 @@
 namespace android {
 namespace uirenderer {
 
-static constexpr size_t UI_THREAD_FRAME_INFO_SIZE = 10;
+static constexpr size_t UI_THREAD_FRAME_INFO_SIZE = 11;
 
 enum class FrameInfoIndex {
     Flags = 0,
@@ -41,6 +41,7 @@ enum class FrameInfoIndex {
     PerformTraversalsStart,
     DrawStart,
     FrameDeadline,
+    FrameStartTime,
     // End of UI frame info
 
     SyncQueued,
diff --git a/libs/hwui/Properties.cpp b/libs/hwui/Properties.cpp
index e58f31fd15eb..7af0a221d228 100644
--- a/libs/hwui/Properties.cpp
+++ b/libs/hwui/Properties.cpp
@@ -81,6 +81,9 @@ bool Properties::isolatedProcess = false;
 int Properties::contextPriority = 0;
 float Properties::defaultSdrWhitePoint = 200.f;
 
+bool Properties::useHintManager = true;
+int Properties::targetCpuTimePercentage = 70;
+
 bool Properties::load() {
     bool prevDebugLayersUpdates = debugLayersUpdates;
     bool prevDebugOverdraw = debugOverdraw;
@@ -128,6 +131,10 @@ bool Properties::load() {
 
     runningInEmulator = base::GetBoolProperty(PROPERTY_IS_EMULATOR, false);
 
+    useHintManager = base::GetBoolProperty(PROPERTY_USE_HINT_MANAGER, true);
+    targetCpuTimePercentage = base::GetIntProperty(PROPERTY_TARGET_CPU_TIME_PERCENTAGE, 70);
+    if (targetCpuTimePercentage <= 0 || targetCpuTimePercentage > 100) targetCpuTimePercentage = 70;
+
     return (prevDebugLayersUpdates != debugLayersUpdates) || (prevDebugOverdraw != debugOverdraw);
 }
 
diff --git a/libs/hwui/Properties.h b/libs/hwui/Properties.h
index ea9cbd592d29..1cb87be98051 100644
--- a/libs/hwui/Properties.h
+++ b/libs/hwui/Properties.h
@@ -158,6 +158,20 @@ enum DebugLevel {
 #define PROPERTY_CAPTURE_SKP_FILENAME "debug.hwui.skp_filename"
 
 /**
+ * Controls whether HWUI will send timing hints to HintManager for
+ * better CPU scheduling. Accepted values are "true" and "false".
+ */
+#define PROPERTY_USE_HINT_MANAGER "debug.hwui.use_hint_manager"
+
+/**
+ * Percentage of frame time that's used for CPU work. The rest is
+ * reserved for GPU work. This is used with use_hint_manager to
+ * provide timing hints to HintManager. Accepted values are
+ * integer from 1-100.
+ */
+#define PROPERTY_TARGET_CPU_TIME_PERCENTAGE "debug.hwui.target_cpu_time_percent"
+
+/**
  * Property for whether this is running in the emulator.
  */
 #define PROPERTY_IS_EMULATOR "ro.boot.qemu"
@@ -253,6 +267,9 @@ public:
 
     static float defaultSdrWhitePoint;
 
+    static bool useHintManager;
+    static int targetCpuTimePercentage;
+
 private:
     static ProfileType sProfileType;
     static bool sDisableProfileBars;
diff --git a/libs/hwui/jni/android_graphics_HardwareRenderer.cpp b/libs/hwui/jni/android_graphics_HardwareRenderer.cpp
index f24ba5c1c878..bd1da985a33e 100644
--- a/libs/hwui/jni/android_graphics_HardwareRenderer.cpp
+++ b/libs/hwui/jni/android_graphics_HardwareRenderer.cpp
@@ -34,14 +34,18 @@
 #include <renderthread/RenderProxy.h>
 #include <renderthread/RenderTask.h>
 #include <renderthread/RenderThread.h>
+#include <thread/CommonPool.h>
 #include <utils/Color.h>
 #include <utils/RefBase.h>
 #include <utils/StrongPointer.h>
 #include <utils/Timers.h>
 #include <utils/TraceUtils.h>
 
+#include <pthread.h>
+
 #include <algorithm>
 #include <atomic>
+#include <vector>
 
 #include "android_graphics_HardwareRendererObserver.h"
 
@@ -53,6 +57,10 @@ using namespace android::uirenderer::renderthread;
 struct {
     jclass clazz;
     jmethodID invokePictureCapturedCallback;
+    jmethodID createHintSession;
+    jmethodID updateTargetWorkDuration;
+    jmethodID reportActualWorkDuration;
+    jmethodID closeHintSession;
 } gHardwareRenderer;
 
 struct {
@@ -71,6 +79,14 @@ static JNIEnv* getenv(JavaVM* vm) {
     return env;
 }
 
+static bool hasExceptionAndClear(JNIEnv* env) {
+    if (GraphicsJNI::hasException(env)) {
+        env->ExceptionClear();
+        return true;
+    }
+    return false;
+}
+
 typedef ANativeWindow* (*ANW_fromSurface)(JNIEnv* env, jobject surface);
 ANW_fromSurface fromSurface;
 
@@ -120,6 +136,67 @@ private:
     }
 };
 
+class HintSessionWrapper : public LightRefBase<HintSessionWrapper> {
+public:
+    static sp<HintSessionWrapper> create(JNIEnv* env, RenderProxy* proxy) {
+        if (!Properties::useHintManager) return nullptr;
+
+        // Include UI thread (self), render thread, and thread pool.
+        std::vector<int> tids = CommonPool::getThreadIds();
+        tids.push_back(proxy->getRenderThreadTid());
+        tids.push_back(pthread_gettid_np(pthread_self()));
+
+        jintArray tidsArray = env->NewIntArray(tids.size());
+        if (hasExceptionAndClear(env)) return nullptr;
+        env->SetIntArrayRegion(tidsArray, 0, tids.size(), reinterpret_cast<jint*>(tids.data()));
+        if (hasExceptionAndClear(env)) return nullptr;
+        jobject session = env->CallStaticObjectMethod(
+                gHardwareRenderer.clazz, gHardwareRenderer.createHintSession, tidsArray);
+        if (hasExceptionAndClear(env) || !session) return nullptr;
+        return new HintSessionWrapper(env, session);
+    }
+
+    ~HintSessionWrapper() {
+        if (!mSession) return;
+        JNIEnv* env = getenv(mVm);
+        env->CallStaticVoidMethod(gHardwareRenderer.clazz, gHardwareRenderer.closeHintSession,
+                                  mSession);
+        hasExceptionAndClear(env);
+        env->DeleteGlobalRef(mSession);
+        mSession = nullptr;
+    }
+
+    void updateTargetWorkDuration(long targetDurationNanos) {
+        if (!mSession) return;
+        JNIEnv* env = getenv(mVm);
+        env->CallStaticVoidMethod(gHardwareRenderer.clazz,
+                                  gHardwareRenderer.updateTargetWorkDuration, mSession,
+                                  static_cast<jlong>(targetDurationNanos));
+        hasExceptionAndClear(env);
+    }
+
+    void reportActualWorkDuration(long actualDurationNanos) {
+        if (!mSession) return;
+        JNIEnv* env = getenv(mVm);
+        env->CallStaticVoidMethod(gHardwareRenderer.clazz,
+                                  gHardwareRenderer.reportActualWorkDuration, mSession,
+                                  static_cast<jlong>(actualDurationNanos));
+        hasExceptionAndClear(env);
+    }
+
+private:
+    HintSessionWrapper(JNIEnv* env, jobject jobject) {
+        env->GetJavaVM(&mVm);
+        if (jobject) {
+            mSession = env->NewGlobalRef(jobject);
+            LOG_ALWAYS_FATAL_IF(!mSession, "Failed to make global ref");
+        }
+    }
+
+    JavaVM* mVm = nullptr;
+    jobject mSession = nullptr;
+};
+
 static void android_view_ThreadedRenderer_rotateProcessStatsBuffer(JNIEnv* env, jobject clazz) {
     RenderProxy::rotateProcessStatsBuffer();
 }
@@ -147,6 +224,12 @@ static jlong android_view_ThreadedRenderer_createProxy(JNIEnv* env, jobject claz
     RootRenderNode* rootRenderNode = reinterpret_cast<RootRenderNode*>(rootRenderNodePtr);
     ContextFactoryImpl factory(rootRenderNode);
     RenderProxy* proxy = new RenderProxy(translucent, rootRenderNode, &factory);
+    sp<HintSessionWrapper> wrapper = HintSessionWrapper::create(env, proxy);
+    if (wrapper) {
+        proxy->setHintSessionCallbacks(
+                [wrapper](int64_t nanos) { wrapper->updateTargetWorkDuration(nanos); },
+                [wrapper](int64_t nanos) { wrapper->reportActualWorkDuration(nanos); });
+    }
     return (jlong) proxy;
 }
 
@@ -769,6 +852,18 @@ int register_android_view_ThreadedRenderer(JNIEnv* env) {
     gHardwareRenderer.invokePictureCapturedCallback = GetStaticMethodIDOrDie(env, hardwareRenderer,
             "invokePictureCapturedCallback",
             "(JLandroid/graphics/HardwareRenderer$PictureCapturedCallback;)V");
+    gHardwareRenderer.createHintSession =
+            GetStaticMethodIDOrDie(env, hardwareRenderer, "createHintSession",
+                                   "([I)Landroid/os/PerformanceHintManager$Session;");
+    gHardwareRenderer.updateTargetWorkDuration =
+            GetStaticMethodIDOrDie(env, hardwareRenderer, "updateTargetWorkDuration",
+                                   "(Landroid/os/PerformanceHintManager$Session;J)V");
+    gHardwareRenderer.reportActualWorkDuration =
+            GetStaticMethodIDOrDie(env, hardwareRenderer, "reportActualWorkDuration",
+                                   "(Landroid/os/PerformanceHintManager$Session;J)V");
+    gHardwareRenderer.closeHintSession =
+            GetStaticMethodIDOrDie(env, hardwareRenderer, "closeHintSession",
+                                   "(Landroid/os/PerformanceHintManager$Session;)V");
 
     jclass frameCallbackClass = FindClassOrDie(env,
             "android/graphics/HardwareRenderer$FrameDrawingCallback");
diff --git a/libs/hwui/renderthread/DrawFrameTask.cpp b/libs/hwui/renderthread/DrawFrameTask.cpp
index 3408ffda3f9d..7a38a3bc9c05 100644
--- a/libs/hwui/renderthread/DrawFrameTask.cpp
+++ b/libs/hwui/renderthread/DrawFrameTask.cpp
@@ -21,6 +21,7 @@
 
 #include "../DeferredLayerUpdater.h"
 #include "../DisplayList.h"
+#include "../Properties.h"
 #include "../RenderNode.h"
 #include "CanvasContext.h"
 #include "RenderThread.h"
@@ -44,6 +45,12 @@ void DrawFrameTask::setContext(RenderThread* thread, CanvasContext* context,
     mTargetNode = targetNode;
 }
 
+void DrawFrameTask::setHintSessionCallbacks(std::function<void(int64_t)> updateTargetWorkDuration,
+                                            std::function<void(int64_t)> reportActualWorkDuration) {
+    mUpdateTargetWorkDuration = std::move(updateTargetWorkDuration);
+    mReportActualWorkDuration = std::move(reportActualWorkDuration);
+}
+
 void DrawFrameTask::pushLayerUpdate(DeferredLayerUpdater* layer) {
     LOG_ALWAYS_FATAL_IF(!mContext,
                         "Lifecycle violation, there's no context to pushLayerUpdate with!");
@@ -102,6 +109,9 @@ void DrawFrameTask::run() {
     CanvasContext* context = mContext;
     std::function<void(int64_t)> callback = std::move(mFrameCallback);
     mFrameCallback = nullptr;
+    int64_t intendedVsync = mFrameInfo[static_cast<int>(FrameInfoIndex::IntendedVsync)];
+    int64_t frameDeadline = mFrameInfo[static_cast<int>(FrameInfoIndex::FrameDeadline)];
+    int64_t frameStartTime = mFrameInfo[static_cast<int>(FrameInfoIndex::FrameStartTime)];
 
     // From this point on anything in "this" is *UNSAFE TO ACCESS*
     if (canUnblockUiThread) {
@@ -124,6 +134,25 @@ void DrawFrameTask::run() {
     if (!canUnblockUiThread) {
         unblockUiThread();
     }
+
+    // These member callbacks are effectively const as they are set once during init, so it's safe
+    // to use these directly instead of making local copies.
+    if (mUpdateTargetWorkDuration && mReportActualWorkDuration) {
+        constexpr int64_t kSanityCheckLowerBound = 100000;       // 0.1ms
+        constexpr int64_t kSanityCheckUpperBound = 10000000000;  // 10s
+        int64_t targetWorkDuration = frameDeadline - intendedVsync;
+        targetWorkDuration = targetWorkDuration * Properties::targetCpuTimePercentage / 100;
+        if (targetWorkDuration > kSanityCheckLowerBound &&
+            targetWorkDuration < kSanityCheckUpperBound &&
+            targetWorkDuration != mLastTargetWorkDuration) {
+            mLastTargetWorkDuration = targetWorkDuration;
+            mUpdateTargetWorkDuration(targetWorkDuration);
+        }
+        int64_t frameDuration = systemTime(SYSTEM_TIME_MONOTONIC) - frameStartTime;
+        if (frameDuration > kSanityCheckLowerBound && frameDuration < kSanityCheckUpperBound) {
+            mReportActualWorkDuration(frameDuration);
+        }
+    }
 }
 
 bool DrawFrameTask::syncFrameState(TreeInfo& info) {
diff --git a/libs/hwui/renderthread/DrawFrameTask.h b/libs/hwui/renderthread/DrawFrameTask.h
index 696cfaef3cd7..3bb574aff59b 100644
--- a/libs/hwui/renderthread/DrawFrameTask.h
+++ b/libs/hwui/renderthread/DrawFrameTask.h
@@ -61,6 +61,8 @@ public:
     virtual ~DrawFrameTask();
 
     void setContext(RenderThread* thread, CanvasContext* context, RenderNode* targetNode);
+    void setHintSessionCallbacks(std::function<void(int64_t)> updateTargetWorkDuration,
+                                 std::function<void(int64_t)> reportActualWorkDuration);
     void setContentDrawBounds(int left, int top, int right, int bottom) {
         mContentDrawBounds.set(left, top, right, bottom);
     }
@@ -107,6 +109,10 @@ private:
 
     std::function<void(int64_t)> mFrameCallback;
     std::function<void(int64_t)> mFrameCompleteCallback;
+
+    nsecs_t mLastTargetWorkDuration = 0;
+    std::function<void(int64_t)> mUpdateTargetWorkDuration;
+    std::function<void(int64_t)> mReportActualWorkDuration;
 };
 
 } /* namespace renderthread */
diff --git a/libs/hwui/renderthread/RenderProxy.cpp b/libs/hwui/renderthread/RenderProxy.cpp
index 423cc08189ca..9361abd20852 100644
--- a/libs/hwui/renderthread/RenderProxy.cpp
+++ b/libs/hwui/renderthread/RenderProxy.cpp
@@ -76,6 +76,12 @@ void RenderProxy::setName(const char* name) {
     mRenderThread.queue().runSync([this, name]() { mContext->setName(std::string(name)); });
 }
 
+void RenderProxy::setHintSessionCallbacks(std::function<void(int64_t)> updateTargetWorkDuration,
+                                          std::function<void(int64_t)> reportActualWorkDuration) {
+    mDrawFrameTask.setHintSessionCallbacks(std::move(updateTargetWorkDuration),
+                                           std::move(reportActualWorkDuration));
+}
+
 void RenderProxy::setSurface(ANativeWindow* window, bool enableTimeout) {
     if (window) { ANativeWindow_acquire(window); }
     mRenderThread.queue().post([this, win = window, enableTimeout]() mutable {
diff --git a/libs/hwui/renderthread/RenderProxy.h b/libs/hwui/renderthread/RenderProxy.h
index 366d6b5a172c..8d55d3c55570 100644
--- a/libs/hwui/renderthread/RenderProxy.h
+++ b/libs/hwui/renderthread/RenderProxy.h
@@ -71,6 +71,8 @@ public:
     void setSwapBehavior(SwapBehavior swapBehavior);
     bool loadSystemProperties();
     void setName(const char* name);
+    void setHintSessionCallbacks(std::function<void(int64_t)> updateTargetWorkDuration,
+                                 std::function<void(int64_t)> reportActualWorkDuration);
 
     void setSurface(ANativeWindow* window, bool enableTimeout = true);
     void setSurfaceControl(ASurfaceControl* surfaceControl);
diff --git a/libs/hwui/thread/CommonPool.cpp b/libs/hwui/thread/CommonPool.cpp
index d011bdfe945e..dc92f9f0d39a 100644
--- a/libs/hwui/thread/CommonPool.cpp
+++ b/libs/hwui/thread/CommonPool.cpp
@@ -29,14 +29,23 @@ CommonPool::CommonPool() {
     ATRACE_CALL();
 
     CommonPool* pool = this;
+    std::mutex mLock;
+    std::vector<int> tids(THREAD_COUNT);
+    std::vector<std::condition_variable> tidConditionVars(THREAD_COUNT);
+
     // Create 2 workers
     for (int i = 0; i < THREAD_COUNT; i++) {
-        std::thread worker([pool, i] {
+        std::thread worker([pool, i, &mLock, &tids, &tidConditionVars] {
             {
                 std::array<char, 20> name{"hwuiTask"};
                 snprintf(name.data(), name.size(), "hwuiTask%d", i);
                 auto self = pthread_self();
                 pthread_setname_np(self, name.data());
+                {
+                    std::unique_lock lock(mLock);
+                    tids[i] = pthread_gettid_np(self);
+                    tidConditionVars[i].notify_one();
+                }
                 setpriority(PRIO_PROCESS, 0, PRIORITY_FOREGROUND);
                 auto startHook = renderthread::RenderThread::getOnStartHook();
                 if (startHook) {
@@ -47,6 +56,15 @@ CommonPool::CommonPool() {
         });
         worker.detach();
     }
+    {
+        std::unique_lock lock(mLock);
+        for (int i = 0; i < THREAD_COUNT; i++) {
+            while (!tids[i]) {
+                tidConditionVars[i].wait(lock);
+            }
+        }
+    }
+    mWorkerThreadIds = std::move(tids);
 }
 
 CommonPool& CommonPool::instance() {
@@ -58,6 +76,10 @@ void CommonPool::post(Task&& task) {
     instance().enqueue(std::move(task));
 }
 
+std::vector<int> CommonPool::getThreadIds() {
+    return instance().mWorkerThreadIds;
+}
+
 void CommonPool::enqueue(Task&& task) {
     std::unique_lock lock(mLock);
     while (!mWorkQueue.hasSpace()) {
@@ -104,4 +126,4 @@ void CommonPool::doWaitForIdle() {
 }
 
 }  // namespace uirenderer
-}  // namespace android
\ No newline at end of file
+}  // namespace android
diff --git a/libs/hwui/thread/CommonPool.h b/libs/hwui/thread/CommonPool.h
index 7603eeef4692..74f852bd1413 100644
--- a/libs/hwui/thread/CommonPool.h
+++ b/libs/hwui/thread/CommonPool.h
@@ -25,6 +25,7 @@
 #include <functional>
 #include <future>
 #include <mutex>
+#include <vector>
 
 namespace android {
 namespace uirenderer {
@@ -97,6 +98,8 @@ public:
         return task.get_future().get();
     };
 
+    static std::vector<int> getThreadIds();
+
     // For testing purposes only, blocks until all worker threads are parked.
     static void waitForIdle();
 
@@ -111,6 +114,8 @@ private:
 
     void workerLoop();
 
+    std::vector<int> mWorkerThreadIds;
+
     std::mutex mLock;
     std::condition_variable mCondition;
     int mWaitingThreads = 0;
diff --git a/services/core/java/com/android/server/power/hint/HintManagerService.java b/services/core/java/com/android/server/power/hint/HintManagerService.java
new file mode 100644
index 000000000000..fc7628c28b8b
--- /dev/null
+++ b/services/core/java/com/android/server/power/hint/HintManagerService.java
@@ -0,0 +1,449 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+package com.android.server.power.hint;
+
+import android.app.ActivityManager;
+import android.app.IUidObserver;
+import android.content.Context;
+import android.os.Binder;
+import android.os.IBinder;
+import android.os.IHintManager;
+import android.os.IHintSession;
+import android.os.Process;
+import android.os.RemoteException;
+import android.util.ArrayMap;
+import android.util.SparseArray;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.DumpUtils;
+import com.android.internal.util.Preconditions;
+import com.android.server.FgThread;
+import com.android.server.SystemService;
+import com.android.server.utils.Slogf;
+
+import java.io.FileDescriptor;
+import java.io.PrintWriter;
+import java.util.Arrays;
+
+/** An hint service implementation that runs in System Server process. */
+public final class HintManagerService extends SystemService {
+    private static final String TAG = "HintManagerService";
+    private static final boolean DEBUG = false;
+    @VisibleForTesting final long mHintSessionPreferredRate;
+
+    @GuardedBy("mLock")
+    private final ArrayMap<Integer, ArrayMap<IBinder, AppHintSession>> mActiveSessions;
+
+    /** Lock to protect HAL handles and listen list. */
+    private final Object mLock = new Object();
+
+    @VisibleForTesting final UidObserver mUidObserver;
+
+    private final NativeWrapper mNativeWrapper;
+
+    @VisibleForTesting final IHintManager.Stub mService = new BinderService();
+
+    public HintManagerService(Context context) {
+        this(context, new Injector());
+    }
+
+    @VisibleForTesting
+    HintManagerService(Context context, Injector injector) {
+        super(context);
+        mActiveSessions = new ArrayMap<>();
+        mNativeWrapper = injector.createNativeWrapper();
+        mNativeWrapper.halInit();
+        mHintSessionPreferredRate = mNativeWrapper.halGetHintSessionPreferredRate();
+        mUidObserver = new UidObserver();
+    }
+
+    @VisibleForTesting
+    static class Injector {
+        NativeWrapper createNativeWrapper() {
+            return new NativeWrapper();
+        }
+    }
+
+    private boolean isHalSupported() {
+        return mHintSessionPreferredRate != -1;
+    }
+
+    @Override
+    public void onStart() {
+        publishBinderService(Context.PERFORMANCE_HINT_SERVICE, mService, /* allowIsolated= */ true);
+    }
+
+    @Override
+    public void onBootPhase(int phase) {
+        if (phase == SystemService.PHASE_SYSTEM_SERVICES_READY) {
+            systemReady();
+        }
+    }
+
+    private void systemReady() {
+        Slogf.v(TAG, "Initializing HintManager service...");
+        try {
+            ActivityManager.getService().registerUidObserver(mUidObserver,
+                    ActivityManager.UID_OBSERVER_PROCSTATE | ActivityManager.UID_OBSERVER_GONE,
+                    ActivityManager.PROCESS_STATE_UNKNOWN, null);
+        } catch (RemoteException e) {
+            // ignored; both services live in system_server
+        }
+
+    }
+
+    /**
+     * Wrapper around the static-native methods from native.
+     *
+     * This class exists to allow us to mock static native methods in our tests. If mocking static
+     * methods becomes easier than this in the future, we can delete this class.
+     */
+    @VisibleForTesting
+    public static class NativeWrapper {
+        private native void nativeInit();
+
+        private static native long nativeCreateHintSession(int tgid, int uid, int[] tids,
+                long durationNanos);
+
+        private static native void nativePauseHintSession(long halPtr);
+
+        private static native void nativeResumeHintSession(long halPtr);
+
+        private static native void nativeCloseHintSession(long halPtr);
+
+        private static native void nativeUpdateTargetWorkDuration(
+                long halPtr, long targetDurationNanos);
+
+        private static native void nativeReportActualWorkDuration(
+                long halPtr, long[] actualDurationNanos, long[] timeStampNanos);
+
+        private static native long nativeGetHintSessionPreferredRate();
+
+        /** Wrapper for HintManager.nativeInit */
+        public void halInit() {
+            nativeInit();
+        }
+
+        /** Wrapper for HintManager.nativeCreateHintSession */
+        public long halCreateHintSession(int tgid, int uid, int[] tids, long durationNanos) {
+            return nativeCreateHintSession(tgid, uid, tids, durationNanos);
+        }
+
+        /** Wrapper for HintManager.nativePauseHintSession */
+        public void halPauseHintSession(long halPtr) {
+            nativePauseHintSession(halPtr);
+        }
+
+        /** Wrapper for HintManager.nativeResumeHintSession */
+        public void halResumeHintSession(long halPtr) {
+            nativeResumeHintSession(halPtr);
+        }
+
+        /** Wrapper for HintManager.nativeCloseHintSession */
+        public void halCloseHintSession(long halPtr) {
+            nativeCloseHintSession(halPtr);
+        }
+
+        /** Wrapper for HintManager.nativeUpdateTargetWorkDuration */
+        public void halUpdateTargetWorkDuration(long halPtr, long targetDurationNanos) {
+            nativeUpdateTargetWorkDuration(halPtr, targetDurationNanos);
+        }
+
+        /** Wrapper for HintManager.nativeReportActualWorkDuration */
+        public void halReportActualWorkDuration(
+                long halPtr, long[] actualDurationNanos, long[] timeStampNanos) {
+            nativeReportActualWorkDuration(halPtr, actualDurationNanos,
+                    timeStampNanos);
+        }
+
+        /** Wrapper for HintManager.nativeGetHintSessionPreferredRate */
+        public long halGetHintSessionPreferredRate() {
+            return nativeGetHintSessionPreferredRate();
+        }
+    }
+
+    @VisibleForTesting
+    final class UidObserver extends IUidObserver.Stub {
+        private final SparseArray<Integer> mProcStatesCache = new SparseArray<>();
+
+        public boolean isUidForeground(int uid) {
+            synchronized (mLock) {
+                return mProcStatesCache.get(uid, ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND)
+                        <= ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
+            }
+        }
+
+        @Override
+        public void onUidGone(int uid, boolean disabled) {
+            FgThread.getHandler().post(() -> {
+                synchronized (mLock) {
+                    ArrayMap<IBinder, AppHintSession> tokenMap = mActiveSessions.get(uid);
+                    if (tokenMap == null) {
+                        return;
+                    }
+                    for (int i = tokenMap.size() - 1; i >= 0; i--) {
+                        // Will remove the session from tokenMap
+                        tokenMap.valueAt(i).close();
+                    }
+                    mProcStatesCache.delete(uid);
+                }
+            });
+        }
+
+        @Override
+        public void onUidActive(int uid) {
+        }
+
+        @Override
+        public void onUidIdle(int uid, boolean disabled) {
+        }
+
+        /**
+         * The IUidObserver callback is called from the system_server, so it'll be a direct function
+         * call from ActivityManagerService. Do not do heavy logic here.
+         */
+        @Override
+        public void onUidStateChanged(int uid, int procState, long procStateSeq, int capability) {
+            FgThread.getHandler().post(() -> {
+                synchronized (mLock) {
+                    mProcStatesCache.put(uid, procState);
+                    ArrayMap<IBinder, AppHintSession> tokenMap = mActiveSessions.get(uid);
+                    if (tokenMap == null) {
+                        return;
+                    }
+                    for (AppHintSession s : tokenMap.values()) {
+                        s.onProcStateChanged();
+                    }
+                }
+            });
+        }
+
+        @Override
+        public void onUidCachedChanged(int uid, boolean cached) {
+        }
+    }
+
+    @VisibleForTesting
+    IHintManager.Stub getBinderServiceInstance() {
+        return mService;
+    }
+
+    private boolean checkTidValid(int tgid, int [] tids) {
+        // Make sure all tids belongs to the same process.
+        for (int threadId : tids) {
+            if (!Process.isThreadInProcess(tgid, threadId)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    @VisibleForTesting
+    final class BinderService extends IHintManager.Stub {
+        @Override
+        public IHintSession createHintSession(IBinder token, int[] tids, long durationNanos) {
+            if (!isHalSupported()) return null;
+
+            java.util.Objects.requireNonNull(token);
+            java.util.Objects.requireNonNull(tids);
+            Preconditions.checkArgument(tids.length != 0, "tids should"
+                    + " not be empty.");
+
+            int uid = Binder.getCallingUid();
+            int tid = Binder.getCallingPid();
+            int pid = Process.getThreadGroupLeader(tid);
+
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                if (!checkTidValid(pid, tids)) {
+                    throw new SecurityException("Some tid doesn't belong to the process");
+                }
+
+                long halSessionPtr = mNativeWrapper.halCreateHintSession(pid, uid, tids,
+                        durationNanos);
+                if (halSessionPtr == 0) return null;
+
+                AppHintSession hs = new AppHintSession(uid, pid, tids, token,
+                        halSessionPtr, durationNanos);
+                synchronized (mLock) {
+                    ArrayMap<IBinder, AppHintSession> tokenMap = mActiveSessions.get(uid);
+                    if (tokenMap == null) {
+                        tokenMap = new ArrayMap<>(1);
+                        mActiveSessions.put(uid, tokenMap);
+                    }
+                    tokenMap.put(token, hs);
+                    return hs;
+                }
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
+        }
+
+        @Override
+        public long getHintSessionPreferredRate() {
+            return mHintSessionPreferredRate;
+        }
+
+        @Override
+        public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
+            if (!DumpUtils.checkDumpPermission(getContext(), TAG, pw)) {
+                return;
+            }
+            synchronized (mLock) {
+                pw.println("HintSessionPreferredRate: " + mHintSessionPreferredRate);
+                pw.println("HAL Support: " + isHalSupported());
+                pw.println("Active Sessions:");
+                for (int i = 0; i < mActiveSessions.size(); i++) {
+                    pw.println("Uid " + mActiveSessions.keyAt(i).toString() + ":");
+                    ArrayMap<IBinder, AppHintSession> tokenMap = mActiveSessions.valueAt(i);
+                    for (int j = 0; j < tokenMap.size(); j++) {
+                        pw.println("  Session " + j + ":");
+                        tokenMap.valueAt(j).dump(pw, "    ");
+                    }
+                }
+            }
+        }
+    }
+
+    @VisibleForTesting
+    final class AppHintSession extends IHintSession.Stub implements IBinder.DeathRecipient {
+        protected final int mUid;
+        protected final int mPid;
+        protected final int[] mThreadIds;
+        protected final IBinder mToken;
+        protected long mHalSessionPtr;
+        protected long mTargetDurationNanos;
+        protected boolean mUpdateAllowed;
+
+        protected AppHintSession(
+                int uid, int pid, int[] threadIds, IBinder token,
+                long halSessionPtr, long durationNanos) {
+            mUid = uid;
+            mPid = pid;
+            mToken = token;
+            mThreadIds = threadIds;
+            mHalSessionPtr = halSessionPtr;
+            mTargetDurationNanos = durationNanos;
+            mUpdateAllowed = true;
+            updateHintAllowed();
+            try {
+                token.linkToDeath(this, 0);
+            } catch (RemoteException e) {
+                mNativeWrapper.halCloseHintSession(mHalSessionPtr);
+                throw new IllegalStateException("Client already dead", e);
+            }
+        }
+
+        @VisibleForTesting
+        boolean updateHintAllowed() {
+            synchronized (mLock) {
+                final boolean allowed = mUidObserver.isUidForeground(mUid);
+                if (allowed && !mUpdateAllowed) resume();
+                if (!allowed && mUpdateAllowed) pause();
+                mUpdateAllowed = allowed;
+                return mUpdateAllowed;
+            }
+        }
+
+        @Override
+        public void updateTargetWorkDuration(long targetDurationNanos) {
+            synchronized (mLock) {
+                if (mHalSessionPtr == 0 || !updateHintAllowed()) {
+                    return;
+                }
+                Preconditions.checkArgument(targetDurationNanos > 0, "Expected"
+                        + " the target duration to be greater than 0.");
+                mNativeWrapper.halUpdateTargetWorkDuration(mHalSessionPtr, targetDurationNanos);
+                mTargetDurationNanos = targetDurationNanos;
+            }
+        }
+
+        @Override
+        public void reportActualWorkDuration(long[] actualDurationNanos, long[] timeStampNanos) {
+            synchronized (mLock) {
+                if (mHalSessionPtr == 0 || !updateHintAllowed()) {
+                    return;
+                }
+                Preconditions.checkArgument(actualDurationNanos.length != 0, "the count"
+                        + " of hint durations shouldn't be 0.");
+                Preconditions.checkArgument(actualDurationNanos.length == timeStampNanos.length,
+                        "The length of durations and timestamps should be the same.");
+                for (int i = 0; i < actualDurationNanos.length; i++) {
+                    if (actualDurationNanos[i] <= 0) {
+                        throw new IllegalArgumentException(
+                                String.format("durations[%d]=%d should be greater than 0",
+                                        i, actualDurationNanos[i]));
+                    }
+                }
+                mNativeWrapper.halReportActualWorkDuration(mHalSessionPtr, actualDurationNanos,
+                        timeStampNanos);
+            }
+        }
+
+        /** TODO: consider monitor session threads and close session if any thread is dead. */
+        @Override
+        public void close() {
+            synchronized (mLock) {
+                if (mHalSessionPtr == 0) return;
+                mNativeWrapper.halCloseHintSession(mHalSessionPtr);
+                mHalSessionPtr = 0;
+                mToken.unlinkToDeath(this, 0);
+                ArrayMap<IBinder, AppHintSession> tokenMap = mActiveSessions.get(mUid);
+                if (tokenMap == null) {
+                    Slogf.w(TAG, "UID %d is note present in active session map", mUid);
+                }
+                tokenMap.remove(mToken);
+                if (tokenMap.isEmpty()) mActiveSessions.remove(mUid);
+            }
+        }
+
+        private void onProcStateChanged() {
+            updateHintAllowed();
+        }
+
+        private void pause() {
+            synchronized (mLock) {
+                if (mHalSessionPtr == 0) return;
+                mNativeWrapper.halPauseHintSession(mHalSessionPtr);
+            }
+        }
+
+        private void resume() {
+            synchronized (mLock) {
+                if (mHalSessionPtr == 0) return;
+                mNativeWrapper.halResumeHintSession(mHalSessionPtr);
+            }
+        }
+
+        private void dump(PrintWriter pw, String prefix) {
+            synchronized (mLock) {
+                pw.println(prefix + "SessionPID: " + mPid);
+                pw.println(prefix + "SessionUID: " + mUid);
+                pw.println(prefix + "SessionTIDs: " + Arrays.toString(mThreadIds));
+                pw.println(prefix + "SessionTargetDurationNanos: " + mTargetDurationNanos);
+                pw.println(prefix + "SessionAllowed: " + updateHintAllowed());
+            }
+        }
+
+        @Override
+        public void binderDied() {
+            close();
+        }
+
+    }
+}
diff --git a/services/core/jni/Android.bp b/services/core/jni/Android.bp
index 15f57653840b..a99679ade958 100644
--- a/services/core/jni/Android.bp
+++ b/services/core/jni/Android.bp
@@ -49,6 +49,7 @@ cc_library_static {
         "com_android_server_net_NetworkStatsService.cpp",
         "com_android_server_power_PowerManagerService.cpp",
         "com_android_server_powerstats_PowerStatsService.cpp",
+        "com_android_server_hint_HintManagerService.cpp",
         "com_android_server_SerialService.cpp",
         "com_android_server_soundtrigger_middleware_AudioSessionProviderImpl.cpp",
         "com_android_server_soundtrigger_middleware_ExternalCaptureStateTracker.cpp",
@@ -158,7 +159,7 @@ cc_defaults {
         "android.hardware.memtrack-V1-ndk_platform",
         "android.hardware.power@1.0",
         "android.hardware.power@1.1",
-        "android.hardware.power-V1-cpp",
+        "android.hardware.power-V2-cpp",
         "android.hardware.power.stats@1.0",
         "android.hardware.power.stats-V1-ndk_platform",
         "android.hardware.thermal@1.0",
@@ -195,8 +196,8 @@ cc_defaults {
                 "libchrome",
                 "libmojo",
             ],
-        }
-    }
+        },
+    },
 }
 
 filegroup {
diff --git a/services/core/jni/com_android_server_hint_HintManagerService.cpp b/services/core/jni/com_android_server_hint_HintManagerService.cpp
new file mode 100644
index 000000000000..000cb839002b
--- /dev/null
+++ b/services/core/jni/com_android_server_hint_HintManagerService.cpp
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#define TAG "HintManagerService-JNI"
+
+//#define LOG_NDEBUG 0
+
+#include <android-base/stringprintf.h>
+#include <android/hardware/power/IPower.h>
+#include <android_runtime/AndroidRuntime.h>
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/ScopedPrimitiveArray.h>
+#include <powermanager/PowerHalController.h>
+#include <utils/Log.h>
+
+#include <unistd.h>
+#include <cinttypes>
+
+#include <sys/types.h>
+
+#include "jni.h"
+
+using android::hardware::power::IPowerHintSession;
+using android::hardware::power::WorkDuration;
+
+using android::base::StringPrintf;
+
+namespace android {
+
+static power::PowerHalController gPowerHalController;
+
+static jlong createHintSession(JNIEnv* env, int32_t tgid, int32_t uid,
+                               std::vector<int32_t> threadIds, int64_t durationNanos) {
+    auto result =
+            gPowerHalController.createHintSession(tgid, uid, std::move(threadIds), durationNanos);
+    if (result.isOk()) {
+        sp<IPowerHintSession> appSession = result.value();
+        if (appSession) appSession->incStrong(env);
+        return reinterpret_cast<jlong>(appSession.get());
+    }
+    return 0;
+}
+
+static void pauseHintSession(JNIEnv* env, int64_t session_ptr) {
+    sp<IPowerHintSession> appSession = reinterpret_cast<IPowerHintSession*>(session_ptr);
+    appSession->pause();
+}
+
+static void resumeHintSession(JNIEnv* env, int64_t session_ptr) {
+    sp<IPowerHintSession> appSession = reinterpret_cast<IPowerHintSession*>(session_ptr);
+    appSession->resume();
+}
+
+static void closeHintSession(JNIEnv* env, int64_t session_ptr) {
+    sp<IPowerHintSession> appSession = reinterpret_cast<IPowerHintSession*>(session_ptr);
+    appSession->close();
+    appSession->decStrong(env);
+}
+
+static void updateTargetWorkDuration(int64_t session_ptr, int64_t targetDurationNanos) {
+    sp<IPowerHintSession> appSession = reinterpret_cast<IPowerHintSession*>(session_ptr);
+    appSession->updateTargetWorkDuration(targetDurationNanos);
+}
+
+static void reportActualWorkDuration(int64_t session_ptr,
+                                     const std::vector<WorkDuration>& actualDurations) {
+    sp<IPowerHintSession> appSession = reinterpret_cast<IPowerHintSession*>(session_ptr);
+    appSession->reportActualWorkDuration(actualDurations);
+}
+
+static int64_t getHintSessionPreferredRate() {
+    int64_t rate = -1;
+    auto result = gPowerHalController.getHintSessionPreferredRate();
+    if (result.isOk()) {
+        rate = result.value();
+    }
+    return rate;
+}
+
+// ----------------------------------------------------------------------------
+static void nativeInit(JNIEnv* env, jobject obj) {
+    gPowerHalController.init();
+}
+
+static jlong nativeCreateHintSession(JNIEnv* env, jclass /* clazz */, jint tgid, jint uid,
+                                     jintArray tids, jlong durationNanos) {
+    ScopedIntArrayRO tidArray(env, tids);
+    if (nullptr == tidArray.get() || tidArray.size() == 0) {
+        ALOGW("GetIntArrayElements returns nullptr.");
+        return 0;
+    }
+    std::vector<int32_t> threadIds(tidArray.size());
+    for (size_t i = 0; i < tidArray.size(); i++) {
+        threadIds[i] = tidArray[i];
+    }
+    return createHintSession(env, tgid, uid, std::move(threadIds), durationNanos);
+}
+
+static void nativePauseHintSession(JNIEnv* env, jclass /* clazz */, jlong session_ptr) {
+    pauseHintSession(env, session_ptr);
+}
+
+static void nativeResumeHintSession(JNIEnv* env, jclass /* clazz */, jlong session_ptr) {
+    resumeHintSession(env, session_ptr);
+}
+
+static void nativeCloseHintSession(JNIEnv* env, jclass /* clazz */, jlong session_ptr) {
+    closeHintSession(env, session_ptr);
+}
+
+static void nativeUpdateTargetWorkDuration(JNIEnv* /* env */, jclass /* clazz */, jlong session_ptr,
+                                           jlong targetDurationNanos) {
+    updateTargetWorkDuration(session_ptr, targetDurationNanos);
+}
+
+static void nativeReportActualWorkDuration(JNIEnv* env, jclass /* clazz */, jlong session_ptr,
+                                           jlongArray actualDurations, jlongArray timeStamps) {
+    ScopedLongArrayRO arrayActualDurations(env, actualDurations);
+    ScopedLongArrayRO arrayTimeStamps(env, timeStamps);
+
+    std::vector<WorkDuration> actualList(arrayActualDurations.size());
+    for (size_t i = 0; i < arrayActualDurations.size(); i++) {
+        actualList[i].timeStampNanos = arrayTimeStamps[i];
+        actualList[i].durationNanos = arrayActualDurations[i];
+    }
+    reportActualWorkDuration(session_ptr, actualList);
+}
+
+static jlong nativeGetHintSessionPreferredRate(JNIEnv* /* env */, jclass /* clazz */) {
+    return static_cast<jlong>(getHintSessionPreferredRate());
+}
+
+// ----------------------------------------------------------------------------
+static const JNINativeMethod sHintManagerServiceMethods[] = {
+        /* name, signature, funcPtr */
+        {"nativeInit", "()V", (void*)nativeInit},
+        {"nativeCreateHintSession", "(II[IJ)J", (void*)nativeCreateHintSession},
+        {"nativePauseHintSession", "(J)V", (void*)nativePauseHintSession},
+        {"nativeResumeHintSession", "(J)V", (void*)nativeResumeHintSession},
+        {"nativeCloseHintSession", "(J)V", (void*)nativeCloseHintSession},
+        {"nativeUpdateTargetWorkDuration", "(JJ)V", (void*)nativeUpdateTargetWorkDuration},
+        {"nativeReportActualWorkDuration", "(J[J[J)V", (void*)nativeReportActualWorkDuration},
+        {"nativeGetHintSessionPreferredRate", "()J", (void*)nativeGetHintSessionPreferredRate},
+};
+
+int register_android_server_HintManagerService(JNIEnv* env) {
+    return jniRegisterNativeMethods(env,
+                                    "com/android/server/power/hint/"
+                                    "HintManagerService$NativeWrapper",
+                                    sHintManagerServiceMethods, NELEM(sHintManagerServiceMethods));
+}
+
+} /* namespace android */
diff --git a/services/core/jni/com_android_server_power_PowerManagerService.cpp b/services/core/jni/com_android_server_power_PowerManagerService.cpp
index 9b7e27d891c4..ae7ea3cd90e8 100644
--- a/services/core/jni/com_android_server_power_PowerManagerService.cpp
+++ b/services/core/jni/com_android_server_power_PowerManagerService.cpp
@@ -100,7 +100,7 @@ static bool setPowerMode(Mode mode, bool enabled) {
         ALOGD("Excessive delay in setting interactive mode to %s while turning screen %s",
               enabled ? "true" : "false", enabled ? "on" : "off");
     }
-    return result == power::HalResult::SUCCESSFUL;
+    return result.isOk();
 }
 
 void android_server_PowerManagerService_userActivity(nsecs_t eventTime, int32_t eventType,
diff --git a/services/core/jni/onload.cpp b/services/core/jni/onload.cpp
index 03a01523b8e2..f257686cbf3d 100644
--- a/services/core/jni/onload.cpp
+++ b/services/core/jni/onload.cpp
@@ -30,6 +30,7 @@ int register_android_server_InputManager(JNIEnv* env);
 int register_android_server_LightsService(JNIEnv* env);
 int register_android_server_PowerManagerService(JNIEnv* env);
 int register_android_server_PowerStatsService(JNIEnv* env);
+int register_android_server_HintManagerService(JNIEnv* env);
 int register_android_server_storage_AppFuse(JNIEnv* env);
 int register_android_server_SerialService(JNIEnv* env);
 int register_android_server_SystemServer(JNIEnv* env);
@@ -79,6 +80,7 @@ extern "C" jint JNI_OnLoad(JavaVM* vm, void* /* reserved */)
     register_android_server_broadcastradio_Tuner(vm, env);
     register_android_server_PowerManagerService(env);
     register_android_server_PowerStatsService(env);
+    register_android_server_HintManagerService(env);
     register_android_server_SerialService(env);
     register_android_server_InputManager(env);
     register_android_server_LightsService(env);
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index 1426579a0f64..47e72ba0e6fc 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -170,6 +170,7 @@ import com.android.server.policy.role.RoleServicePlatformHelperImpl;
 import com.android.server.power.PowerManagerService;
 import com.android.server.power.ShutdownThread;
 import com.android.server.power.ThermalManagerService;
+import com.android.server.power.hint.HintManagerService;
 import com.android.server.powerstats.PowerStatsService;
 import com.android.server.profcollect.ProfcollectForwardingService;
 import com.android.server.recoverysystem.RecoverySystemService;
@@ -1074,6 +1075,10 @@ public final class SystemServer implements Dumpable {
         mSystemServiceManager.startService(ThermalManagerService.class);
         t.traceEnd();
 
+        t.traceBegin("StartHintManager");
+        mSystemServiceManager.startService(HintManagerService.class);
+        t.traceEnd();
+
         // Now that the power manager has been started, let the activity manager
         // initialize power management features.
         t.traceBegin("InitPowerManagement");
diff --git a/services/tests/servicestests/src/com/android/server/power/hint/HintManagerServiceTest.java b/services/tests/servicestests/src/com/android/server/power/hint/HintManagerServiceTest.java
new file mode 100644
index 000000000000..aaf40d7e4461
--- /dev/null
+++ b/services/tests/servicestests/src/com/android/server/power/hint/HintManagerServiceTest.java
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+package com.android.server.power.hint;
+
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeFalse;
+import static org.junit.Assume.assumeTrue;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.anyLong;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.reset;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.ActivityManager;
+import android.content.Context;
+import android.os.Binder;
+import android.os.IBinder;
+import android.os.IHintSession;
+import android.os.Process;
+
+import com.android.server.FgThread;
+import com.android.server.power.hint.HintManagerService.AppHintSession;
+import com.android.server.power.hint.HintManagerService.Injector;
+import com.android.server.power.hint.HintManagerService.NativeWrapper;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+/**
+ * Tests for {@link com.android.server.power.hint.HintManagerService}.
+ *
+ * Build/Install/Run:
+ *  atest FrameworksServicesTests:HintManagerServiceTest
+ */
+public class HintManagerServiceTest {
+    private static final long DEFAULT_HINT_PREFERRED_RATE = 16666666L;
+    private static final long DEFAULT_TARGET_DURATION = 16666666L;
+    private static final int UID = Process.myUid();
+    private static final int TID = Process.myPid();
+    private static final int TGID = Process.getThreadGroupLeader(TID);
+    private static final int[] SESSION_TIDS_A = new int[] {TID};
+    private static final int[] SESSION_TIDS_B = new int[] {TID};
+    private static final long[] DURATIONS_THREE = new long[] {1L, 100L, 1000L};
+    private static final long[] TIMESTAMPS_THREE = new long[] {1L, 2L, 3L};
+    private static final long[] DURATIONS_ZERO = new long[] {};
+    private static final long[] TIMESTAMPS_ZERO = new long[] {};
+    private static final long[] TIMESTAMPS_TWO = new long[] {1L, 2L};
+
+    @Mock private Context mContext;
+    @Mock private HintManagerService.NativeWrapper mNativeWrapperMock;
+
+    private HintManagerService mService;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        when(mNativeWrapperMock.halGetHintSessionPreferredRate())
+                .thenReturn(DEFAULT_HINT_PREFERRED_RATE);
+        when(mNativeWrapperMock.halCreateHintSession(eq(TGID), eq(UID), eq(SESSION_TIDS_A),
+              eq(DEFAULT_TARGET_DURATION))).thenReturn(1L);
+        when(mNativeWrapperMock.halCreateHintSession(eq(TGID), eq(UID), eq(SESSION_TIDS_B),
+              eq(DEFAULT_TARGET_DURATION))).thenReturn(2L);
+    }
+
+    private HintManagerService createService() {
+        mService = new HintManagerService(mContext, new Injector() {
+            NativeWrapper createNativeWrapper() {
+                return mNativeWrapperMock;
+            }
+        });
+        return mService;
+    }
+
+    @Test
+    public void testInitializeService() {
+        HintManagerService service = createService();
+        verify(mNativeWrapperMock).halInit();
+        assertThat(service.mHintSessionPreferredRate).isEqualTo(DEFAULT_HINT_PREFERRED_RATE);
+    }
+
+    @Test
+    public void testCreateHintSession() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        IHintSession a = service.getBinderServiceInstance().createHintSession(token,
+                SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+        assertNotNull(a);
+
+        IHintSession b = service.getBinderServiceInstance().createHintSession(token,
+                SESSION_TIDS_B, DEFAULT_TARGET_DURATION);
+        assertNotEquals(a, b);
+    }
+
+    @Test
+    public void testPauseResumeHintSession() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        AppHintSession a = (AppHintSession) service.getBinderServiceInstance()
+                .createHintSession(token, SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        // Set session to background and calling updateHintAllowed() would invoke pause();
+        service.mUidObserver.onUidStateChanged(
+                a.mUid, ActivityManager.PROCESS_STATE_TRANSIENT_BACKGROUND, 0, 0);
+        final Object sync = new Object();
+        FgThread.getHandler().post(() -> {
+            synchronized (sync) {
+                sync.notify();
+            }
+        });
+        synchronized (sync) {
+            sync.wait();
+        }
+        assumeFalse(a.updateHintAllowed());
+        verify(mNativeWrapperMock, times(1)).halPauseHintSession(anyLong());
+
+        // Set session to foreground and calling updateHintAllowed() would invoke resume();
+        service.mUidObserver.onUidStateChanged(
+                a.mUid, ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND, 0, 0);
+        FgThread.getHandler().post(() -> {
+            synchronized (sync) {
+                sync.notify();
+            }
+        });
+        synchronized (sync) {
+            sync.wait();
+        }
+        assumeTrue(a.updateHintAllowed());
+        verify(mNativeWrapperMock, times(1)).halResumeHintSession(anyLong());
+    }
+
+    @Test
+    public void testCloseHintSession() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        IHintSession a = service.getBinderServiceInstance().createHintSession(token,
+                SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        a.close();
+        verify(mNativeWrapperMock, times(1)).halCloseHintSession(anyLong());
+    }
+
+    @Test
+    public void testUpdateTargetWorkDuration() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        IHintSession a = service.getBinderServiceInstance().createHintSession(token,
+                SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            a.updateTargetWorkDuration(-1L);
+        });
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            a.updateTargetWorkDuration(0L);
+        });
+
+        a.updateTargetWorkDuration(100L);
+        verify(mNativeWrapperMock, times(1)).halUpdateTargetWorkDuration(anyLong(), eq(100L));
+    }
+
+    @Test
+    public void testReportActualWorkDuration() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        AppHintSession a = (AppHintSession) service.getBinderServiceInstance()
+                .createHintSession(token, SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        a.updateTargetWorkDuration(100L);
+        a.reportActualWorkDuration(DURATIONS_THREE, TIMESTAMPS_THREE);
+        verify(mNativeWrapperMock, times(1)).halReportActualWorkDuration(anyLong(),
+                eq(DURATIONS_THREE), eq(TIMESTAMPS_THREE));
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            a.reportActualWorkDuration(DURATIONS_ZERO, TIMESTAMPS_THREE);
+        });
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            a.reportActualWorkDuration(DURATIONS_THREE, TIMESTAMPS_ZERO);
+        });
+
+        assertThrows(IllegalArgumentException.class, () -> {
+            a.reportActualWorkDuration(DURATIONS_THREE, TIMESTAMPS_TWO);
+        });
+
+        reset(mNativeWrapperMock);
+        // Set session to background, then the duration would not be updated.
+        service.mUidObserver.onUidStateChanged(
+                a.mUid, ActivityManager.PROCESS_STATE_TRANSIENT_BACKGROUND, 0, 0);
+        final Object sync = new Object();
+        FgThread.getHandler().post(() -> {
+            synchronized (sync) {
+                sync.notify();
+            }
+        });
+        synchronized (sync) {
+            sync.wait();
+        }
+        assumeFalse(a.updateHintAllowed());
+        a.reportActualWorkDuration(DURATIONS_THREE, TIMESTAMPS_THREE);
+        verify(mNativeWrapperMock, never()).halReportActualWorkDuration(anyLong(), any(), any());
+    }
+
+    @Test
+    public void testDoHintInBackground() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        AppHintSession a = (AppHintSession) service.getBinderServiceInstance()
+                .createHintSession(token, SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        service.mUidObserver.onUidStateChanged(
+                a.mUid, ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND, 0, 0);
+        final Object sync = new Object();
+        FgThread.getHandler().post(() -> {
+            synchronized (sync) {
+                sync.notify();
+            }
+        });
+        synchronized (sync) {
+            sync.wait();
+        }
+        assertFalse(a.updateHintAllowed());
+    }
+
+    @Test
+    public void testDoHintInForeground() throws Exception {
+        HintManagerService service = createService();
+        IBinder token = new Binder();
+
+        AppHintSession a = (AppHintSession) service.getBinderServiceInstance()
+                .createHintSession(token, SESSION_TIDS_A, DEFAULT_TARGET_DURATION);
+
+        service.mUidObserver.onUidStateChanged(
+                a.mUid, ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND, 0, 0);
+        assertTrue(a.updateHintAllowed());
+    }
+}