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 HeapMonitorStatCorrectnessTest.java 31 * @run main/othervm/native -agentlib:HeapMonitor MyPackage.HeapMonitorStatCorrectnessTest 32 */ 33 34 import java.io.PrintStream; 35 36 public class HeapMonitorStatCorrectnessTest { 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 // Do 100000 iterations and expect maxIteration / multiplier samples. 50 public static final int maxIteration = 100000; 51 public static int array[]; 52 53 native static int statsNull(); 54 native static int statsHaveSamples(int expected, int percentError); 55 native static int enableSampling(int rate); 56 native static int disableSampling(); 57 58 59 private static void allocate(int size) { 60 System.out.println("With a size of " + size + ", execute " + maxIteration + " iterations"); 61 for (int j = 0; j < maxIteration; j++) { 62 array = new int[size]; 63 } 64 } 65 66 public static void main(String[] args) { 67 int sizes[] = {1000, 10000, 100000}; 68 69 for (int i = 0; i < sizes.length; i++) { 70 int currentSize = sizes[i]; 71 System.out.println("Testing size " + currentSize); 72 73 // 111 is as good a number as any. 74 final int samplingMultiplier = 111; 75 enableSampling(samplingMultiplier * currentSize); 76 77 if (statsNull() == 0) { 78 throw new RuntimeException("Statistics should be null to begin with."); 79 } 80 81 allocate(currentSize); 82 83 // For simplifications, we ignore the array memory usage for array internals (with the array 84 // sizes requested, it should be a negligible oversight). 85 // 86 // That means that with maxIterations, the loop in the method allocate requests: 87 // maxIterations * currentSize * 4 bytes (4 for integers) 88 // 89 // Via the enable sampling, the code requests a sample every samplingMultiplier * currentSize bytes. 90 // 91 // Therefore, the expected sample number is: 92 // (maxIterations * currentSize * 4) / (samplingMultiplier * currentSize); 93 double expected = maxIteration; 94 expected *= 4; 95 expected /= samplingMultiplier; 96 97 // 10% error ensures a sanity test without becoming flaky. 98 if (statsHaveSamples((int) expected, 10) != 0) { 99 throw new RuntimeException("Statistics should show about " + expected + " samples."); 100 } 101 102 disableSampling(); 103 } 104 } 105 }