1 /*
   2  * Copyright (c) 2017, Google 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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package MyPackage;
  25 
  26 /**
  27  * @test
  28  * @summary Verifies the JVMTI Heap Monitor Thread sanity
  29  * @compile HeapMonitorThreadOnOffTest.java
  30  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorThreadOnOffTest
  31  */
  32 
  33 import java.io.PrintStream;
  34 import java.util.ArrayList;
  35 import java.util.List;
  36 
  37 public class HeapMonitorThreadOnOffTest {
  38   static {
  39     try {
  40       System.loadLibrary("HeapMonitor");
  41     } catch (UnsatisfiedLinkError ule) {
  42       System.err.println("Could not load HeapMonitor library");
  43       System.err.println("java.library.path: "
  44           + System.getProperty("java.library.path"));
  45       throw ule;
  46     }
  47   }
  48 
  49   public static void main(String[] args) {
  50     final int numThreads = 24;
  51     ArrayList<Thread> list = new ArrayList<>();
  52 
  53     // Add one thread that consistently turns on/off the sampler to ensure correctness with
  54     // potential resets.
  55     Switch switchPlayer = new Switch();
  56     Thread switchThread = new Thread(switchPlayer, "Switch Player");
  57     switchThread.start();
  58 
  59     for (int i = 0 ; i < numThreads; i++) {
  60       Thread thread = new Thread(new Allocator(i), "Allocator" + i);
  61       thread.start();
  62       list.add(thread);
  63     }
  64 
  65     for (Thread elem : list) {
  66       try {
  67         elem.join();
  68       } catch(InterruptedException e) {
  69         throw new RuntimeException("Thread got interrupted...");
  70       }
  71     }
  72 
  73     switchPlayer.stop();
  74     try {
  75       switchThread.join();
  76     } catch(InterruptedException e) {
  77       throw new RuntimeException("Thread got interrupted while waiting for the switch player...");
  78     }
  79 
  80     // We don't check here for correctness of data. If we made it here, the test succeeded:
  81     //  Threads can allocate like crazy
  82     //  Other threads can turn on/off the system
  83   }
  84 }
  85 
  86 class Allocator implements Runnable {
  87   private int depth;
  88   private int g_tmp[];
  89 
  90   public Allocator(int depth) {
  91     this.depth = depth;
  92   }
  93 
  94   private int helper() {
  95     int sum = 0;
  96     // Let us assume that the array is 24 bytes of memory.
  97     for (int i = 0; i < 127000 / 6; i++) {
  98       int tmp[] = new int[1];
  99       // Force it to be kept.
 100       g_tmp = tmp;
 101       sum += g_tmp[0];
 102     }
 103     return sum;
 104   }
 105 
 106   private int recursiveWrapper(int depth) {
 107     if (depth > 0) {
 108       return recursiveWrapper(depth - 1);
 109     }
 110     return helper();
 111   }
 112 
 113   public void run() {
 114     int sum = 0;
 115     System.err.println("Runner with " + depth + " depth.");
 116     for (int j = 0; j < 500; j++) {
 117       sum += recursiveWrapper(depth);
 118     }
 119     System.err.println("Ran with " + depth + " depth and sum is " + sum);
 120   }
 121 }
 122 
 123 class Switch implements Runnable {
 124   private volatile boolean keepGoing;
 125 
 126   private native static void enableSampling();
 127   private native static void disableSampling();
 128 
 129   public Switch() {
 130     keepGoing = true;
 131   }
 132 
 133   public void stop() {
 134     keepGoing = false;
 135   }
 136 
 137   public void run() {
 138     int cnt = 0;
 139     System.err.println("Going to turned on/off sampling.");
 140     while (keepGoing) {
 141       disableSampling();
 142       enableSampling();
 143       cnt++;
 144     }
 145     System.err.println("Turned on/off " + cnt + " times.");
 146   }
 147 }