| /* |
| * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * @test TestFullGCount.java |
| * @bug 7072527 |
| * @summary CMS: JMM GC counters overcount in some cases |
| * @run main/othervm -XX:+PrintGC TestFullGCCount |
| */ |
| import java.util.*; |
| import java.lang.management.*; |
| |
| /* |
| * Originally for a specific failure in CMS, this test now monitors all |
| * collectors for double-counting of collections. |
| */ |
| public class TestFullGCCount { |
| |
| static List<GarbageCollectorMXBean> collectors = ManagementFactory.getGarbageCollectorMXBeans(); |
| |
| public static void main(String[] args) { |
| int iterations = 20; |
| boolean failed = false; |
| String errorMessage = ""; |
| HashMap<String, List> counts = new HashMap<String, List>(); |
| |
| // Prime the collection of count lists for all collectors. |
| for (int i = 0; i < collectors.size(); i++) { |
| GarbageCollectorMXBean collector = collectors.get(i); |
| counts.put(collector.getName(), new ArrayList<Long>(iterations)); |
| } |
| |
| // Perform some gc, record collector counts. |
| for (int i = 0; i < iterations; i++) { |
| System.gc(); |
| addCollectionCount(counts, i); |
| } |
| |
| // Check the increments: |
| // Old gen collectors should increase by one, |
| // New collectors may or may not increase. |
| // Any increase >=2 is unexpected. |
| for (String collector : counts.keySet()) { |
| System.out.println("Checking: " + collector); |
| |
| for (int i = 0; i < iterations - 1; i++) { |
| List<Long> theseCounts = counts.get(collector); |
| long a = theseCounts.get(i); |
| long b = theseCounts.get(i + 1); |
| if (b - a >= 2) { |
| failed = true; |
| errorMessage += "Collector '" + collector + "' has increment " + (b - a) + |
| " at iteration " + i + "\n"; |
| } |
| } |
| } |
| if (failed) { |
| System.err.println(errorMessage); |
| throw new RuntimeException("FAILED: System.gc collections miscounted."); |
| } |
| System.out.println("Passed."); |
| } |
| |
| private static void addCollectionCount(HashMap<String, List> counts, int iteration) { |
| for (int i = 0; i < collectors.size(); i++) { |
| GarbageCollectorMXBean collector = collectors.get(i); |
| List thisList = counts.get(collector.getName()); |
| thisList.add(collector.getCollectionCount()); |
| } |
| } |
| } |