1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2018, Google and/or its affiliates. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 */ 24 25 package MyPackage; 26 27 /** 28 * @test 29 * @summary Verifies the JVMTI Heap Monitor sampling interval average. 30 * @build Frame HeapMonitor 31 * @compile HeapMonitorStatIntervalTest.java 32 * @requires vm.compMode != "Xcomp" 33 * @run main/othervm/native -agentlib:HeapMonitorTest MyPackage.HeapMonitorStatIntervalTest 34 */ 35 36 public class HeapMonitorStatIntervalTest { testIntervalOnce(int interval, boolean throwIfFailure)37 private static boolean testIntervalOnce(int interval, boolean throwIfFailure) { 38 HeapMonitor.resetEventStorage(); 39 HeapMonitor.setSamplingInterval(interval); 40 41 HeapMonitor.enableSamplingEvents(); 42 43 int allocationTotal = 10 * 1024 * 1024; 44 int allocationIterations = 10; 45 46 double actualCount = 0; 47 for (int i = 0; i < allocationIterations; i++) { 48 HeapMonitor.resetEventStorage(); 49 HeapMonitor.allocateSize(allocationTotal); 50 actualCount += HeapMonitor.getEventStorageElementCount(); 51 } 52 53 HeapMonitor.disableSamplingEvents(); 54 55 double expectedCount = allocationTotal * allocationIterations / interval; 56 57 double error = Math.abs(actualCount - expectedCount); 58 double errorPercentage = error / expectedCount * 100; 59 60 boolean success = (errorPercentage < 10.0); 61 System.out.println("Interval: " + interval + ", throw if failure: " + throwIfFailure 62 + " - Expected count: " + expectedCount + ", allocationIterations: " + allocationIterations 63 + ", actualCount: " + actualCount + " -> " + success); 64 65 if (!success && throwIfFailure) { 66 throw new RuntimeException("Interval average over 10% for interval " + interval + " -> " 67 + actualCount + ", " + expectedCount); 68 } 69 70 return success; 71 } 72 73 testInterval(int interval)74 private static void testInterval(int interval) { 75 // Test the interval twice, it can happen that the test is "unlucky" and the interval just goes above 76 // the 10% mark. So try again to squash flakiness. 77 // Flakiness is due to the fact that this test is dependent on the sampling interval, which is a 78 // statistical geometric variable around the sampling interval. This means that the test could be 79 // unlucky and not achieve the mean average fast enough for the test case. 80 if (!testIntervalOnce(interval, false)) { 81 testIntervalOnce(interval, true); 82 } 83 } 84 main(String[] args)85 public static void main(String[] args) { 86 int[] tab = {1024, 8192}; 87 88 HeapMonitor.calculateOneElementSize(); 89 90 for (int intervalIdx = 0; intervalIdx < tab.length; intervalIdx++) { 91 testInterval(tab[intervalIdx]); 92 } 93 } 94 } 95