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 Statistics
  29  * @build Frame
  30  * @compile HeapMonitorStatRateTest.java
  31  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatRateTest
  32  */
  33 
  34 import java.io.PrintStream;
  35 
  36 public class HeapMonitorStatRateTest {
  37 
  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   native static double getAverageRate();
  50   native static int enableSampling(int rate);
  51   native static void disableSampling();
  52 
  53   public static int cnt;
  54   public static int g_tmp[];
  55   public int array[];
  56 
  57   public static int helper() {
  58     int sum = 0;
  59     // Let us assume that the array is 24 bytes of memory.
  60     for (int i = 0; i < 127000 / 6; i++) {
  61       int tmp[] = new int[1];
  62       // Force it to be kept.
  63       g_tmp = tmp;
  64       sum += g_tmp[0];
  65     }
  66     return sum;
  67   }
  68 
  69   public static void wrapper() {
  70     int sum = 0;
  71     for (int j = 0; j < 5000; j++) {
  72       sum += helper();
  73     }
  74     System.out.println(sum);
  75   }
  76 
  77   public static void main(String[] args) {
  78     int[] tab = {1024, 16384, 524288};
  79 
  80     for (int rateIdx = 0; rateIdx < tab.length; rateIdx++) {
  81       int rate = tab[rateIdx];
  82 
  83       enableSampling(rate);
  84       wrapper();
  85       disableSampling();
  86 
  87       double calculatedRate = getAverageRate();
  88 
  89       double error = rate - calculatedRate;
  90       error = error < 0 ? -error : error;
  91 
  92       double errorPercentage = error / rate * 100;
  93 
  94       if (errorPercentage > 5) {
  95         throw new RuntimeException("Rate average over 5% for rate " + rate);
  96       }
  97     }
  98   }
  99 }