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comparison test/gc/7072527/TestFullGCCount.java @ 3827:41e6ee74f879

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7072527: CMS: JMM GC counters overcount in some cases Summary: Avoid overcounting when CMS has concurrent mode failure. Reviewed-by: ysr Contributed-by: rednaxelafx@gmail.com
author kevinw
date Tue, 02 Aug 2011 14:37:35 +0100
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children bfe3be9ebd6c
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3803:0defeba52583 3827:41e6ee74f879
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