Add perf tests for LooperStats

Test: n/a
Change-Id: I97e290398ca67d3fda0ffeae723c2cb2d0bc10f3

apct-tests/perftests/core/src/android/os/LooperStatsPerfTest.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2018 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.perftests.utils.BenchmarkState;
+import android.perftests.utils.PerfStatusReporter;
+import android.support.test.filters.LargeTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.android.internal.os.CachedDeviceState;
+import com.android.internal.os.LooperStats;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+
+/**
+ * Performance tests for {@link LooperStats}.
+ */
+@RunWith(AndroidJUnit4.class)
+@LargeTest
+public class LooperStatsPerfTest {
+    private static final int DISTINCT_MESSAGE_COUNT = 1000;
+
+    @Rule
+    public PerfStatusReporter mPerfStatusReporter = new PerfStatusReporter();
+    private LooperStats mStats;
+    private CachedDeviceState mDeviceState;
+    private HandlerThread mThread;
+    private Message[] mMessages = new Message[DISTINCT_MESSAGE_COUNT];
+
+    @Before
+    public void setUp() {
+        mStats = new LooperStats(1, DISTINCT_MESSAGE_COUNT - 1);
+        mDeviceState = new CachedDeviceState(false, false);
+        mStats.setDeviceState(mDeviceState.getReadonlyClient());
+        // The tests are all single-threaded. HandlerThread is created to allow creating Handlers.
+        mThread = new HandlerThread("UnusedThread");
+        mThread.start();
+        for (int i = 0; i < DISTINCT_MESSAGE_COUNT; i++) {
+            mMessages[i] = mThread.getThreadHandler().obtainMessage(i);
+        }
+    }
+
+    @After
+    public void tearDown() {
+        mThread.quit();
+    }
+
+    @Test
+    public void timeHundredPercentSampling() {
+        mStats.setSamplingInterval(1);
+        runScenario();
+    }
+
+    @Test
+    public void timeOnePercentSampling() {
+        mStats.setSamplingInterval(100);
+        runScenario();
+    }
+
+    @Test
+    public void timeCollectionDisabled() {
+        // We do not collect data on charger.
+        mDeviceState.setCharging(true);
+        runScenario();
+    }
+
+    private void runScenario() {
+        final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
+        while (state.keepRunning()) {
+            for (int i = 0; i < DISTINCT_MESSAGE_COUNT; i++) {
+                Object token = mStats.messageDispatchStarting();
+                mStats.messageDispatched(token, mMessages[i]);
+            }
+        }
+    }
+}