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 HeapMonitorThreadTest.java
  30  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorThreadTest
  31  */
  32 
  33 import java.io.PrintStream;
  34 import java.util.ArrayList;
  35 import java.util.List;
  36 
  37 public class HeapMonitorThreadTest {
  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   private native static boolean checkSamples(int[] threads);
  50   private native static void enableSampling();
  51 
  52   public static void main(String[] args) {
  53     final int numThreads = 24;
  54     ArrayList<Thread> list = new ArrayList<>();
  55 
  56     enableSampling();
  57 
  58     for (int i = 0 ; i < numThreads; i++) {
  59       Thread thread = new Thread(new Allocator(i), "Allocator" + i);
  60       thread.start();
  61       list.add(thread);
  62     }
  63 
  64     for (Thread elem : list) {
  65       try {
  66         elem.join();
  67       } catch(InterruptedException e) {
  68         throw new RuntimeException("Thread got interrupted...");
  69       }
  70     }
  71 
  72     int[] threads = new int[numThreads];
  73     if (!checkSamples(threads)) {
  74       throw new RuntimeException("Problem with checkSamples...");
  75     }
  76 
  77     for (int elem : threads) {
  78       if (elem == 0) {
  79         throw new RuntimeException("Missing at least one thread in the array...");
  80       }
  81     }
  82   }
  83 }
  84 
  85 class Allocator implements Runnable {
  86   private int depth;
  87   private int g_tmp[];
  88 
  89   public Allocator(int depth) {
  90     this.depth = depth;
  91   }
  92 
  93   private int helper() {
  94     int sum = 0;
  95     // Let us assume that the array is 24 bytes of memory.
  96     for (int i = 0; i < 127000 / 6; i++) {
  97       int tmp[] = new int[1];
  98       // Force it to be kept.
  99       g_tmp = tmp;
 100       sum += g_tmp[0];
 101     }
 102     return sum;
 103   }
 104 
 105   private int recursiveWrapper(int depth) {
 106     if (depth > 0) {
 107       return recursiveWrapper(depth - 1);
 108     }
 109     return helper();
 110   }
 111 
 112   public void run() {
 113     int sum = 0;
 114     for (int j = 0; j < 50; j++) {
 115       sum += recursiveWrapper(depth);
 116     }
 117     System.out.println(sum);
 118   }
 119 }