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 * @summary Verifies the JVMTI Heap Monitor sampling rate average. 29 * @build Frame HeapMonitor 30 * @compile HeapMonitorStatRateTest.java 31 * @requires vm.compMode != "Xcomp" 32 * @run main/othervm/native -agentlib:HeapMonitorTest MyPackage.HeapMonitorStatRateTest 33 */ 34 35 public class HeapMonitorStatRateTest { 36 37 private native static double getAverageRate(); 38 39 private static boolean testRateOnce(int rate, boolean throwIfFailure) { 40 HeapMonitor.resetEventStorage(); 41 HeapMonitor.setSamplingRate(rate); 42 43 HeapMonitor.enableSamplingEvents(); 44 45 int allocationTotal = 10 * 1024 * 1024; 46 HeapMonitor.allocateSize(allocationTotal); 47 48 HeapMonitor.disableSamplingEvents(); 49 50 double actualCount = HeapMonitor.getEventStorageElementCount(); 51 double expectedCount = allocationTotal / rate; 52 53 double error = Math.abs(actualCount - expectedCount); 54 double errorPercentage = error / expectedCount * 100; 55 56 boolean failure = (errorPercentage > 10.0); 57 58 if (failure && throwIfFailure) { 59 throw new RuntimeException("Rate average over 10% for rate " + rate + " -> " + actualCount 60 + ", " + expectedCount); 61 } 62 63 return failure; 64 } 65 66 67 private static void testRate(int rate) { 68 // Test the rate twice, it can happen that the test is "unlucky" and the rate just goes above 69 // the 10% mark. So try again to squash flakiness. 70 // Flakiness is due to the fact that this test is dependent on the sampling rate, which is a 71 // statistical geometric variable around the sampling rate. This means that the test could be 72 // unlucky and not achieve the mean average fast enough for the test case. 73 if (!testRateOnce(rate, false)) { 74 testRateOnce(rate, true); 75 } 76 } 77 78 public static void main(String[] args) { 79 int[] tab = {1024, 8192}; 80 81 for (int rateIdx = 0; rateIdx < tab.length; rateIdx++) { 82 testRate(tab[rateIdx]); 83 } 84 } 85 }