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 sampling rate average
  29  * @build Frame HeapMonitor
  30  * @compile HeapMonitorStatRateTest.java
  31  * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatRateTest
  32  */
  33 
  34 public class HeapMonitorStatRateTest {
  35 
  36   private native static double getAverageRate();
  37 
  38   public static void main(String[] args) {
  39     int[] tab = {1024, 16384, 524288};
  40 
  41     for (int rateIdx = 0; rateIdx < tab.length; rateIdx++) {
  42       int rate = tab[rateIdx];
  43 
  44       HeapMonitor.enableSampling(rate);
  45       HeapMonitor.allocate();
  46       HeapMonitor.disableSampling();
  47 
  48       double calculatedRate = getAverageRate();
  49 
  50       double error = rate - calculatedRate;
  51       error = error < 0 ? -error : error;
  52 
  53       double errorPercentage = error / rate * 100;
  54 
  55       if (errorPercentage > 5) {
  56         throw new RuntimeException("Rate average over 5% for rate " + rate + " -> " + calculatedRate);
  57       }
  58     }
  59   }
  60 }