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 Checks the frequent garbage storage system.
  29  * @build Frame
  30  * @compile HeapMonitorFrequentTest.java
  31  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorFrequentTest
  32  */
  33 
  34 public class HeapMonitorFrequentTest {
  35 
  36   static {
  37     try {
  38       System.loadLibrary("HeapMonitor");
  39     } catch (UnsatisfiedLinkError ule) {
  40       System.err.println("Could not load HeapMonitor library");
  41       System.err.println("java.library.path: "
  42           + System.getProperty("java.library.path"));
  43       throw ule;
  44     }
  45   }
  46 
  47   private native static int checkFrequentFrames(Frame[] frames);
  48   private native static int enableSampling();
  49 
  50   private static int g_tmp[];
  51 
  52   private static int helper() {
  53     int sum = 0;
  54     // Let us assume that the array is 24 bytes of memory.
  55     for (int i = 0; i < 127000 / 6; i++) {
  56       int tmp[] = new int[1];
  57       // Force it to be kept.
  58       g_tmp = tmp;
  59       sum += g_tmp[0];
  60     }
  61     return sum;
  62   }
  63 
  64   private static void runner(int max) {
  65     int sum = 0;
  66     for (int j = 0; j < max; j++) {
  67       sum += helper();
  68     }
  69     System.out.println(sum);
  70   }
  71 
  72   public static void main(String[] args) {
  73     Frame[] frames = new Frame[3];
  74     frames[0] = new Frame("helper", "()I", "HeapMonitorRecentTest.java", 60);
  75     frames[1] = new Frame("runner", "(I)V", "HeapMonitorRecentTest.java", 71);
  76     frames[2] = new Frame("main", "([Ljava/lang/String;)V", "HeapMonitorRecentTest.java", 85);
  77 
  78     enableSampling();
  79     // We are testing for the recent garbage sampler:
  80     // First run for 10000 iterations to fill up the garbage sampler.
  81     runner(10000);
  82 
  83     // Now because we are in a different stack frame line here, we can just re-use the same runner.
  84     // Run for 3, we really should not see that many of these and most should be the first type.
  85     runner(5000);
  86 
  87     // Both types should exist in frequent since it was frequent enough.
  88     int status = checkFrequentFrames(frames);
  89     if (status == 0) {
  90       throw new RuntimeException("Old frames no longer exist");
  91     }
  92 
  93     // Change the last frame only since the rest is identical.
  94     frames[2].lineNumber = 89;
  95 
  96     status = checkFrequentFrames(frames);
  97     if (status == 0) {
  98       throw new RuntimeException("New frames not in the frequent sampling list");
  99     }
 100   }
 101 }