1 /* 2 * Copyright (c) 2018, 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 * @build Frame HeapMonitor 29 * @summary Verifies the JVMTI Heap Monitor sampling via object allocation. 30 * @compile HeapMonitorStatObjectCorrectnessTest.java 31 * @run main/othervm/native -agentlib:HeapMonitorTest MyPackage.HeapMonitorStatObjectCorrectnessTest 32 */ 33 34 /** This test is checking the object allocation path works with heap sampling. */ 35 public class HeapMonitorStatObjectCorrectnessTest { 36 37 // Do 200000 iterations and expect maxIteration / multiplier samples. 38 private static final int maxIteration = 200000; 39 private static BigObject obj; 40 41 private native static boolean statsHaveExpectedNumberSamples(int expected, int percentError); 42 43 private static void allocate() { 44 for (int j = 0; j < maxIteration; j++) { 45 obj = new BigObject(); 46 } 47 } 48 49 private static void testBigAllocationRate() { 50 final int sizeObject = 1400; 51 52 // 111 is as good a number as any. 53 final int samplingMultiplier = 111; 54 HeapMonitor.setSamplingRate(samplingMultiplier * sizeObject); 55 56 emptyStorage(); 57 allocate(); 58 59 // For simplifications, the code is allocating: 60 // (BigObject size) * maxIteration. 61 // 62 // We ignore the class memory usage apart from field memory usage for BigObject. BigObject 63 // allocates 250 long, so 2000 bytes, so whatever is used for the class is negligible. 64 // 65 // That means that with maxIterations, the loop in the method allocate requests: 66 // maxIterations * 2000 bytes. 67 // 68 // Via the enable sampling, the code requests a sample every samplingMultiplier * sizeObject bytes. 69 // 70 // Therefore, the expected sample number is: 71 // (maxIterations * sizeObject) / (samplingMultiplier * sizeObject); 72 // 73 // Which becomes: 74 // maxIterations / samplingMultiplier 75 double expected = maxIteration; 76 expected /= samplingMultiplier; 77 78 // 10% error ensures a sanity test without becoming flaky. 79 // Flakiness is due to the fact that this test is dependent on the sampling rate, which is a 80 // statistical geometric variable around the sampling rate. This means that the test could be 81 // unlucky and not achieve the mean average fast enough for the test case. 82 if (!HeapMonitor.statsHaveExpectedNumberSamples((int) expected, 10)) { 83 throw new RuntimeException("Statistics should show about " + expected + " samples."); 84 } 85 } 86 87 private static void emptyStorage() { 88 HeapMonitor.resetEventStorage(); 89 90 if (!HeapMonitor.eventStorageIsEmpty()) { 91 throw new RuntimeException("Statistics should be null to begin with."); 92 } 93 } 94 95 private static void testEveryAllocationSampled() { 96 // 0 means sample every allocation. 97 HeapMonitor.setSamplingRate(0); 98 99 emptyStorage(); 100 allocate(); 101 102 double expected = maxIteration; 103 104 // 10% error ensures a sanity test without becoming flaky. 105 // Flakiness is due to the fact that this test is dependent on the sampling rate, which is a 106 // statistical geometric variable around the sampling rate. This means that the test could be 107 // unlucky and not achieve the mean average fast enough for the test case. 108 if (!HeapMonitor.statsHaveExpectedNumberSamples((int) expected, 10)) { 109 throw new RuntimeException("Statistics should show about " + expected + " samples."); 110 } 111 } 112 113 public static void main(String[] args) { 114 HeapMonitor.enableSamplingEvents(); 115 116 testBigAllocationRate(); 117 testEveryAllocationSampled(); 118 } 119 120 /** 121 * Big class on purpose to just be able to ignore the class memory space overhead. 122 * 123 * Class contains 175 long fields, so 175 * 8 = 1400 bytes. 124 */ 125 private static class BigObject { 126 private long a0_0, a0_1, a0_2, a0_3, a0_4, a0_5, a0_6, a0_7, a0_8, a0_9; 127 private long a1_0, a1_1, a1_2, a1_3, a1_4, a1_5, a1_6, a1_7, a1_8, a1_9; 128 private long a2_0, a2_1, a2_2, a2_3, a2_4, a2_5, a2_6, a2_7, a2_8, a2_9; 129 private long a3_0, a3_1, a3_2, a3_3, a3_4, a3_5, a3_6, a3_7, a3_8, a3_9; 130 private long a4_0, a4_1, a4_2, a4_3, a4_4, a4_5, a4_6, a4_7, a4_8, a4_9; 131 private long a5_0, a5_1, a5_2, a5_3, a5_4, a5_5, a5_6, a5_7, a5_8, a5_9; 132 private long a6_0, a6_1, a6_2, a6_3, a6_4, a6_5, a6_6, a6_7, a6_8, a6_9; 133 private long a7_0, a7_1, a7_2, a7_3, a7_4, a7_5, a7_6, a7_7, a7_8, a7_9; 134 private long a8_0, a8_1, a8_2, a8_3, a8_4, a8_5, a8_6, a8_7, a8_8, a8_9; 135 private long a9_0, a9_1, a9_2, a9_3, a9_4, a9_5, a9_6, a9_7, a9_8, a9_9; 136 private long a10_0, a10_1, a10_2, a10_3, a10_4, a10_5, a10_6, a10_7, a10_8, a10_9; 137 private long a11_0, a11_1, a11_2, a11_3, a11_4, a11_5, a11_6, a11_7, a11_8, a11_9; 138 private long a12_0, a12_1, a12_2, a12_3, a12_4, a12_5, a12_6, a12_7, a12_8, a12_9; 139 private long a13_0, a13_1, a13_2, a13_3, a13_4, a13_5, a13_6, a13_7, a13_8, a13_9; 140 private long a14_0, a14_1, a14_2, a14_3, a14_4, a14_5, a14_6, a14_7, a14_8, a14_9; 141 private long a15_0, a15_1, a15_2, a15_3, a15_4, a15_5, a15_6, a15_7, a15_8, a15_9; 142 private long a16_0, a16_1, a16_2, a16_3, a16_4, a16_5, a16_6, a16_7, a16_8, a16_9; 143 private long a17_0, a17_1, a17_2, a17_3, a17_4; 144 } 145 }