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 * @compile HeapMonitorStatCorrectnessTest.java 30 * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatCorrectnessTest 31 */ 32 33 public class HeapMonitorStatCorrectnessTest { 34 35 static { 36 try { 37 System.loadLibrary("HeapMonitor"); 38 } catch (UnsatisfiedLinkError ule) { 39 System.err.println("Could not load HeapMonitor library"); 40 System.err.println("java.library.path: " 41 + System.getProperty("java.library.path")); 42 throw ule; 43 } 44 } 45 46 // Do 100000 iterations and expect maxIteration / multiplier samples. 47 private static final int maxIteration = 100000; 48 private static int array[]; 49 50 private native static int statsNull(); 51 private native static int statsHaveSamples(int expected, int percentError); 52 private native static int enableSampling(int rate); 53 private native static int disableSampling(); 54 55 private static void allocate(int size) { 56 System.out.println("With a size of " + size + ", execute " + maxIteration + " iterations"); 57 for (int j = 0; j < maxIteration; j++) { 58 array = new int[size]; 59 } 60 } 61 62 public static void main(String[] args) { 63 int sizes[] = {1000, 10000, 100000}; 64 65 for (int i = 0; i < sizes.length; i++) { 66 int currentSize = sizes[i]; 67 System.out.println("Testing size " + currentSize); 68 69 // 111 is as good a number as any. 70 final int samplingMultiplier = 111; 71 enableSampling(samplingMultiplier * currentSize); 72 73 if (statsNull() == 0) { 74 throw new RuntimeException("Statistics should be null to begin with."); 75 } 76 77 allocate(currentSize); 78 79 // For simplifications, we ignore the array memory usage for array internals (with the array 80 // sizes requested, it should be a negligible oversight). 81 // 82 // That means that with maxIterations, the loop in the method allocate requests: 83 // maxIterations * currentSize * 4 bytes (4 for integers) 84 // 85 // Via the enable sampling, the code requests a sample every samplingMultiplier * currentSize bytes. 86 // 87 // Therefore, the expected sample number is: 88 // (maxIterations * currentSize * 4) / (samplingMultiplier * currentSize); 89 double expected = maxIteration; 90 expected *= 4; 91 expected /= samplingMultiplier; 92 93 // 10% error ensures a sanity test without becoming flaky. 94 if (statsHaveSamples((int) expected, 10) != 0) { 95 throw new RuntimeException("Statistics should show about " + expected + " samples."); 96 } 97 98 disableSampling(); 99 } 100 } 101 }