Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.internal.os; |
| 18 | |
| 19 | import static org.junit.Assert.assertEquals; |
| 20 | import static org.junit.Assert.assertNotNull; |
| 21 | import static org.junit.Assert.assertTrue; |
| 22 | |
Misha Wagner | 4b32c9f | 2019-01-25 15:30:14 +0000 | [diff] [blame] | 23 | import android.os.Process; |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 24 | import android.os.SystemClock; |
Tadashi G. Takaoka | 7a4047f | 2019-02-02 09:55:59 +0900 | [diff] [blame] | 25 | |
| 26 | import androidx.test.ext.junit.runners.AndroidJUnit4; |
| 27 | import androidx.test.filters.LargeTest; |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 28 | |
| 29 | import com.android.internal.os.KernelCpuThreadReader.ProcessCpuUsage; |
| 30 | import com.android.internal.os.KernelCpuThreadReader.ThreadCpuUsage; |
| 31 | |
| 32 | import org.junit.Test; |
| 33 | import org.junit.runner.RunWith; |
| 34 | |
| 35 | import java.time.Duration; |
| 36 | import java.util.Arrays; |
| 37 | import java.util.List; |
Misha Wagner | 3989eb0 | 2019-03-19 11:05:37 +0000 | [diff] [blame^] | 38 | import java.util.Optional; |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 39 | import java.util.OptionalDouble; |
| 40 | import java.util.concurrent.CountDownLatch; |
| 41 | import java.util.function.Consumer; |
| 42 | import java.util.stream.Collectors; |
| 43 | |
| 44 | /** |
| 45 | * End to end test for {@link KernelCpuThreadReader} that checks the accuracy of the reported times |
| 46 | * by spawning threads that do a predictable amount of work |
| 47 | */ |
| 48 | @RunWith(AndroidJUnit4.class) |
| 49 | @LargeTest |
| 50 | public class KernelCpuThreadReaderEndToEndTest { |
| 51 | |
| 52 | private static final int TIMED_NUM_SAMPLES = 5; |
| 53 | private static final int TIMED_START_MILLIS = 500; |
| 54 | private static final int TIMED_END_MILLIS = 2000; |
| 55 | private static final int TIMED_INCREMENT_MILLIS = 500; |
| 56 | private static final int TIMED_COMPARISON_DELTA_MILLIS = 200; |
| 57 | |
| 58 | private static final int ITERATIVE_NUM_SAMPLES = 100; |
| 59 | private static final long ITERATIVE_LOW_ITERATIONS = (long) 1e8; |
| 60 | private static final long ITERATIVE_HIGH_ITERATIONS = (long) 2e8; |
| 61 | private static final double ITERATIONS_COMPARISONS_DELTA = 0.25; |
| 62 | |
| 63 | /** |
| 64 | * Test that when we busy-wait for the thread-local time to reach N seconds, the time reported |
| 65 | * is also N seconds. Takes ~10s. |
| 66 | */ |
| 67 | @Test |
| 68 | public void testTimedWork() throws InterruptedException { |
| 69 | for (int millis = TIMED_START_MILLIS; |
| 70 | millis <= TIMED_END_MILLIS; |
| 71 | millis += TIMED_INCREMENT_MILLIS) { |
| 72 | final Duration targetDuration = Duration.ofMillis(millis); |
| 73 | final Runnable work = timedWork(targetDuration); |
| 74 | Duration resultDuration = getAverageWorkTime( |
| 75 | work, String.format("timed%dms", millis), TIMED_NUM_SAMPLES); |
| 76 | assertEquals( |
| 77 | "Time worked according to currentThreadTimeMillis doesn't match " |
| 78 | + "KernelCpuThreadReader", |
| 79 | targetDuration.toMillis(), resultDuration.toMillis(), |
| 80 | TIMED_COMPARISON_DELTA_MILLIS); |
| 81 | } |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * Test that when we scale up the amount of work by N, the time reported also scales by N. Takes |
| 86 | * ~15s. |
| 87 | */ |
| 88 | @Test |
| 89 | public void testIterativeWork() throws InterruptedException { |
| 90 | final Runnable lowAmountWork = iterativeWork(ITERATIVE_LOW_ITERATIONS); |
| 91 | final Runnable highAmountWork = iterativeWork(ITERATIVE_HIGH_ITERATIONS); |
| 92 | final Duration lowResultDuration = |
| 93 | getAverageWorkTime(lowAmountWork, "iterlow", ITERATIVE_NUM_SAMPLES); |
| 94 | final Duration highResultDuration = |
| 95 | getAverageWorkTime(highAmountWork, "iterhigh", ITERATIVE_NUM_SAMPLES); |
| 96 | assertEquals( |
| 97 | "Work scale and CPU time scale do not match", |
| 98 | ((double) ITERATIVE_HIGH_ITERATIONS) / ((double) ITERATIVE_LOW_ITERATIONS), |
| 99 | ((double) highResultDuration.toMillis()) / ((double) lowResultDuration.toMillis()), |
| 100 | ITERATIONS_COMPARISONS_DELTA); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Run some work {@code numSamples} times, and take the average CPU duration used for that work |
| 105 | * according to {@link KernelCpuThreadReader} |
| 106 | */ |
| 107 | private Duration getAverageWorkTime( |
| 108 | Runnable work, String tag, int numSamples) throws InterruptedException { |
| 109 | // Count down every time a thread finishes work, so that we can wait for work to complete |
| 110 | final CountDownLatch workFinishedLatch = new CountDownLatch(numSamples); |
| 111 | // Count down once when threads can terminate (after we get them from |
| 112 | // `KernelCpuThreadReader`) |
| 113 | final CountDownLatch threadFinishedLatch = new CountDownLatch(1); |
| 114 | |
| 115 | // Start `NUM_SAMPLE` threads to do the work |
| 116 | for (int i = 0; i < numSamples; i++) { |
| 117 | final String threadName = String.format("%s%d", tag, i); |
| 118 | // Check the thread name, as we rely on it later to identify threads |
| 119 | assertTrue("Max name length for linux threads is 15", threadName.length() <= 15); |
| 120 | doWork(work, threadName, workFinishedLatch, threadFinishedLatch); |
| 121 | } |
| 122 | |
| 123 | // Wait for threads to finish |
| 124 | workFinishedLatch.await(); |
| 125 | |
| 126 | // Get thread data from KernelCpuThreadReader |
Misha Wagner | 4b32c9f | 2019-01-25 15:30:14 +0000 | [diff] [blame] | 127 | final KernelCpuThreadReader kernelCpuThreadReader = |
Misha Wagner | 648d203 | 2019-02-11 10:43:27 +0000 | [diff] [blame] | 128 | KernelCpuThreadReader.create(8, uid -> uid == Process.myUid(), 0); |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 129 | assertNotNull(kernelCpuThreadReader); |
Misha Wagner | 3989eb0 | 2019-03-19 11:05:37 +0000 | [diff] [blame^] | 130 | kernelCpuThreadReader.setUidPredicate(uid -> uid == Process.myUid()); |
| 131 | final Optional<ProcessCpuUsage> currentProcessCpuUsage = |
| 132 | kernelCpuThreadReader.getProcessCpuUsage().stream() |
| 133 | .filter(p -> p.processId == Process.myPid()) |
| 134 | .findFirst(); |
| 135 | assertTrue(currentProcessCpuUsage.isPresent()); |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 136 | |
| 137 | // Threads can terminate, as we've finished crawling them from /proc |
| 138 | threadFinishedLatch.countDown(); |
| 139 | |
| 140 | // Check that we've got times for every thread we spawned |
Misha Wagner | 3989eb0 | 2019-03-19 11:05:37 +0000 | [diff] [blame^] | 141 | final List<ThreadCpuUsage> threadCpuUsages = |
| 142 | currentProcessCpuUsage.get().threadCpuUsages.stream() |
| 143 | .filter((thread) -> thread.threadName.startsWith(tag)) |
| 144 | .collect(Collectors.toList()); |
Misha Wagner | 6923643 | 2019-01-07 14:13:24 +0000 | [diff] [blame] | 145 | assertEquals( |
| 146 | "Incorrect number of threads returned by KernelCpuThreadReader", |
| 147 | numSamples, threadCpuUsages.size()); |
| 148 | |
| 149 | // Calculate the average time spent working |
| 150 | final OptionalDouble averageWorkTimeMillis = threadCpuUsages.stream() |
| 151 | .mapToDouble((t) -> Arrays.stream(t.usageTimesMillis).sum()) |
| 152 | .average(); |
| 153 | assertTrue(averageWorkTimeMillis.isPresent()); |
| 154 | return Duration.ofMillis((long) averageWorkTimeMillis.getAsDouble()); |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * Work that lasts {@code duration} according to {@link SystemClock#currentThreadTimeMillis()} |
| 159 | */ |
| 160 | private Runnable timedWork(Duration duration) { |
| 161 | return () -> { |
| 162 | // Busy loop until `duration` has elapsed for the thread timer |
| 163 | final long startTimeMillis = SystemClock.currentThreadTimeMillis(); |
| 164 | final long durationMillis = duration.toMillis(); |
| 165 | while (true) { |
| 166 | final long elapsedMillis = SystemClock.currentThreadTimeMillis() - startTimeMillis; |
| 167 | if (elapsedMillis >= durationMillis) { |
| 168 | break; |
| 169 | } |
| 170 | } |
| 171 | }; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Work that iterates {@code iterations} times |
| 176 | */ |
| 177 | private Runnable iterativeWork(long iterations) { |
| 178 | Consumer<Long> empty = (i) -> { |
| 179 | }; |
| 180 | return () -> { |
| 181 | long count = 0; |
| 182 | for (long i = 0; i < iterations; i++) { |
| 183 | // Alternate branching to reduce effect of branch prediction |
| 184 | if (i % 2 == 0) { |
| 185 | count++; |
| 186 | } |
| 187 | } |
| 188 | // Call empty function with value to avoid loop getting optimized away |
| 189 | empty.accept(count); |
| 190 | }; |
| 191 | } |
| 192 | |
| 193 | /** |
| 194 | * Perform some work in another thread |
| 195 | * |
| 196 | * @param work the work to perform |
| 197 | * @param threadName the name of the spawned thread |
| 198 | * @param workFinishedLatch latch to register that the work has been completed |
| 199 | * @param threadFinishedLatch latch to pause termination of the thread until the latch is |
| 200 | * decremented |
| 201 | */ |
| 202 | private void doWork( |
| 203 | Runnable work, |
| 204 | String threadName, |
| 205 | CountDownLatch workFinishedLatch, |
| 206 | CountDownLatch threadFinishedLatch) { |
| 207 | Runnable workWrapped = () -> { |
| 208 | // Do the work |
| 209 | work.run(); |
| 210 | // Notify that the work is finished |
| 211 | workFinishedLatch.countDown(); |
| 212 | // Wait until `threadFinishLatch` has been released in order to keep the thread alive so |
| 213 | // we can see it in `proc` filesystem |
| 214 | try { |
| 215 | threadFinishedLatch.await(); |
| 216 | } catch (InterruptedException e) { |
| 217 | e.printStackTrace(); |
| 218 | } |
| 219 | }; |
| 220 | new Thread(workWrapped, threadName).start(); |
| 221 | } |
| 222 | } |