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 * @compile HeapMonitorStatRateTest.java 30 * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatRateTest 31 */ 32 33 public class HeapMonitorStatRateTest { 34 static { 35 try { 36 System.loadLibrary("HeapMonitor"); 37 } catch (UnsatisfiedLinkError ule) { 38 System.err.println("Could not load HeapMonitor library"); 39 System.err.println("java.library.path: " 40 + System.getProperty("java.library.path")); 41 throw ule; 42 } 43 } 44 45 private static int g_tmp[]; 46 47 private native static double getAverageRate(); 48 private native static int enableSampling(int rate); 49 private native static void disableSampling(); 50 51 private static int helper() { 52 int sum = 0; 53 // Let us assume that the array is 24 bytes of memory. 54 for (int i = 0; i < 127000 / 6; i++) { 55 int tmp[] = new int[1]; 56 // Force it to be kept. 57 g_tmp = tmp; 58 sum += g_tmp[0]; 59 } 60 return sum; 61 } 62 63 private static void wrapper() { 64 int sum = 0; 65 for (int j = 0; j < 5000; j++) { 66 sum += helper(); 67 } 68 System.out.println(sum); 69 } 70 71 public static void main(String[] args) { 72 int[] tab = {1024, 16384, 524288}; 73 74 for (int rateIdx = 0; rateIdx < tab.length; rateIdx++) { 75 int rate = tab[rateIdx]; 76 77 enableSampling(rate); 78 wrapper(); 79 disableSampling(); 80 81 double calculatedRate = getAverageRate(); 82 83 double error = rate - calculatedRate; 84 error = error < 0 ? -error : error; 85 86 double errorPercentage = error / rate * 100; 87 88 if (errorPercentage > 5) { 89 throw new RuntimeException("Rate average over 5% for rate " + rate); 90 } 91 } 92 } 93 }