1 /* 2 * Copyright (c) 2011, Oracle 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 /* 25 * @test TestFullGCount.java 26 * @bug 7072527 27 * @summary CMS: JMM GC counters overcount in some cases 28 * @run main/othervm -XX:+UseConcMarkSweepGC TestFullGCCount 29 * 30 */ 31 import java.util.*; 32 import java.lang.management.*; 33 34 public class TestFullGCCount { 35 36 public String collectorName = "ConcurrentMarkSweep"; 37 38 public static void main(String [] args) { 39 40 TestFullGCCount t = null; 41 if (args.length==2) { 42 t = new TestFullGCCount(args[0], args[1]); 43 } else { 44 t = new TestFullGCCount(); 45 } 46 System.out.println("Monitoring collector: " + t.collectorName); 47 t.run(); 48 } 49 50 public TestFullGCCount(String pool, String collector) { 51 collectorName = collector; 52 } 53 54 public TestFullGCCount() { 55 } 56 57 public void run() { 58 int count = 0; 59 int iterations = 20; 60 long counts[] = new long[iterations]; 61 boolean diffAlways2 = true; // assume we will fail 62 63 for (int i=0; i<iterations; i++) { 64 System.gc(); 65 counts[i] = getCollectionCount(); 66 if (i>0) { 67 if (counts[i] - counts[i-1] != 2) { 68 diffAlways2 = false; 69 } 70 } 71 } 72 if (diffAlways2) { 73 throw new RuntimeException("FAILED: System.gc must be incrementing count twice."); 74 } 75 System.out.println("Passed."); 76 } 77 78 private long getCollectionCount() { 79 long count = 0; 80 List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans(); 81 List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans(); 82 for (int i=0; i<collectors.size(); i++) { 83 GarbageCollectorMXBean collector = collectors.get(i); 84 String name = collector.getName(); 85 if (name.contains(collectorName)) { 86 System.out.println(name + ": collection count = " 87 + collector.getCollectionCount()); 88 count = collector.getCollectionCount(); 89 } 90 } 91 return count; 92 } 93 94 } 95