1 /*

     2  * Copyright (c) 2013, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package jdk.jfr.event.runtime;

    27 

    28 import static jdk.test.lib.Asserts.assertGreaterThan;

    29 import static jdk.test.lib.Asserts.assertTrue;

    30 

    31 import java.lang.management.ManagementFactory;

    32 import java.time.Duration;

    33 import java.util.Collections;

    34 import java.util.List;

    35 import java.util.Random;

    36 import java.util.concurrent.CountDownLatch;

    37 

    38 import com.sun.management.ThreadMXBean;

    39 

    40 import jdk.jfr.Recording;

    41 import jdk.jfr.consumer.RecordedEvent;

    42 import jdk.jfr.consumer.RecordedThread;

    43 import jdk.test.lib.jfr.EventNames;

    44 import jdk.test.lib.jfr.Events;

    45 

    46 /*

    47  * @test

    48  * @key jfr

    49  * @library /test/lib

    50  * @modules jdk.jfr

    51  *          jdk.management

    52  *

    53  * @run main/othervm -XX:-UseTLAB jdk.jfr.event.runtime.TestThreadAllocationEvent

    54  */

    55 

    56 /**

    57  * The test will create a few threads that will allocate memory for a short time.

    58  * During this time a number of thread_allocation events will be generated.

    59  * The test will verify:

    60  * 1. That number of allocated bytes is not decreasing for a thread.

    61  *  - This assumption is only true when not using TLABs. For this reason the

    62  *    test is run with -XX:-UseTLAB. When using TLABs, the code calculating the

    63  *    allocated bytes is using the current TLAB to do as good of an approximation

    64  *    as possible, but this introduces a race which might double count the current

    65  *    TLAB when it is full and in the middle of being switched out.

    66  * 2. That sum of allocated bytes approximately matches value in ThreadMXBean.

    67  */

    68 public class TestThreadAllocationEvent {

    69     private static final String EVENT_NAME = EventNames.ThreadAllocationStatistics;

    70     private static final String testThreadName = "testThread-";

    71     private static final long eventPeriodMillis = 50;

    72 

    73     // The value in both the JFR event and in the ThreadMXBean is documented as

    74     // an "approximation" of number of bytes allocated.

    75     // To not give any false errors, we allow an error margin of 5 mb.

    76     // The test will typically allocate over 600 mb, so 5 mb is an error of less than 1%.

    77     private static final long allowedTotalAllocatedDiff = 5000000;

    78 

    79     public static void main(String[] args) throws Throwable {

    80         Recording recording = new Recording();

    81         recording.enable(EVENT_NAME).withPeriod(Duration.ofMillis(eventPeriodMillis));

    82         recording.start();

    83 

    84         AllocatorThread[] threads = new AllocatorThread[4];

    85         CountDownLatch allocationsDoneLatch = new CountDownLatch(threads.length);

    86         for (int i = 0; i < threads.length; i++) {

    87             threads[i] = new AllocatorThread(allocationsDoneLatch, 1000 * (i + 1));

    88             threads[i].setName(testThreadName + i);

    89             threads[i].setDaemon(true);

    90             threads[i].start();

    91         }

    92 

    93         // Take regular measurements while the threads are allocating memory.

    94         // Stop measurement when all threads are ready.

    95         try {

    96             allocationsDoneLatch.await();

    97         } catch (InterruptedException e) {

    98             e.printStackTrace();

    99         }

   100         // Verify that number of allocated bytes is not decreasing.

   101         recording.stop();

   102         verifyAllocationsNotDecreasing(Events.fromRecording(recording), threads);

   103 

   104         // Now allocations are done and threads are waiting to die.

   105         // Make a new instant recording to get total number of allocated bytes.

   106         // The reason for this extra recording is to make sure we get a JFR event

   107         // after all allocations are done so we can compare the JFR value with

   108         // the value reported by ThreadMXBean.

   109         recording = new Recording();

   110         recording.enable(EVENT_NAME);

   111         recording.start();

   112         recording.stop();

   113         verifyTotalAllocated(Events.fromRecording(recording), threads);

   114     }

   115 

   116     /**

   117      * Verify that the allocated value never decreases.

   118      * We only compare our own allocator threads. The reason for that is that other threads

   119      * may start/stop at any time, and we do not know if other thread names are unique.

   120      */

   121      private static void verifyAllocationsNotDecreasing(List<RecordedEvent> events, AllocatorThread[] threads) {

   122          Collections.sort(events, (u,v) -> u.getEndTime().compareTo(v.getEndTime()));

   123          long[] prevAllocated = new long[threads.length];

   124          for (RecordedEvent event : events) {

   125              RecordedThread rt = Events.assertField(event, "thread").notNull().getValue(); // Check that we have a thread.

   126              String name = rt.getJavaName();

   127              for (int i = 0; i < threads.length; i++) {

   128                  if (name.equals(threads[i].getName())) {

   129                      long curr = Events.assertField(event, "allocated").atLeast(prevAllocated[i]).getValue();

   130                      prevAllocated[i] = curr;

   131                  }

   132              }

   133          }

   134 

   135          for (int i = 0; i < threads.length; i++) {

   136              assertGreaterThan(prevAllocated[i], 0L, "No allocations for thread " + threads[i].getName());

   137          }

   138      }

   139 

   140      /**

   141       * Verify that total allocated bytes in JFR event approximately matches the value in ThreadMXBean.

   142       */

   143     private static void verifyTotalAllocated(List<RecordedEvent> events, AllocatorThread[] threads) {

   144         boolean[] isEventFound = new boolean[threads.length];

   145         for (RecordedEvent event : events) {

   146             RecordedThread rt = Events.assertField(event, "thread").notNull().getValue();

   147             String name = rt.getJavaName();

   148             for (int i = 0; i < threads.length; ++i) {

   149                 if (name.equals(threads[i].getName())) {

   150                     System.out.println("Event:" + event);

   151                     long maxAllowed = threads[i].totalAllocated + allowedTotalAllocatedDiff;

   152                     long minAllowed = Math.max(0, threads[i].totalAllocated - allowedTotalAllocatedDiff);

   153                     Events.assertField(event, "allocated").atLeast(minAllowed).atMost(maxAllowed);

   154                     isEventFound[i] = true;

   155                 }

   156             }

   157         }

   158         for (int i = 0; i < threads.length; ++i) {

   159             assertTrue(isEventFound[i], "No event for thread id " + i);

   160         }

   161     }

   162 

   163     /**

   164      * Thread that does a number of allocations and records total number of

   165      * bytes allocated as reported by ThreadMXBean.

   166      */

   167     public static class AllocatorThread extends Thread {

   168         private volatile long totalAllocated = -1;

   169         private final int averageAllocationSize;

   170         public byte[] buffer;

   171         private final CountDownLatch allocationsDoneLatch;

   172 

   173         public AllocatorThread(CountDownLatch allocationsDoneLatch, int averageAllocationSize) {

   174             this.allocationsDoneLatch = allocationsDoneLatch;

   175             this.averageAllocationSize = averageAllocationSize;

   176         }

   177 

   178         @Override

   179         public void run() {

   180             Random rand = new Random();

   181             int allocationSizeBase = averageAllocationSize / 2;

   182             int allocationSizeRandom = averageAllocationSize;

   183             for (int batches=0; batches<100; batches++) {

   184                 for (int i=0; i<1500; i++) {

   185                     buffer = new byte[rand.nextInt(allocationSizeRandom) + allocationSizeBase];

   186                 }

   187                 try {

   188                     // No need to allocate too much data between JFR events, so do a short sleep.

   189                     Thread.sleep(eventPeriodMillis / 5);

   190                 } catch (InterruptedException e) {

   191                     e.printStackTrace();

   192                 }

   193             }

   194             totalAllocated = getThreadAllocatedBytes();

   195             allocationsDoneLatch.countDown();

   196 

   197             // Need to keep thread alive so we can get the final JFR event.

   198             // This is a daemon thread, so it will finish when the main thread finishes.

   199             while (true) {

   200                 Thread.yield();

   201             }

   202         }

   203 

   204         private long getThreadAllocatedBytes() {

   205             ThreadMXBean bean = (ThreadMXBean) ManagementFactory.getThreadMXBean();

   206             return bean.getThreadAllocatedBytes(Thread.currentThread().getId());

   207         }

   208     }

   209 

   210 }