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comparison test/gc/g1/TestHumongousShrinkHeap.java @ 20381:09e9e5240710

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8037925: CMM Testing: an allocated humongous object at the end of the heap should not prevents shrinking the heap Summary: New test added. Reviewed-by: ehelin, tschatzl, jwilhelm Contributed-by: andrey.x.zakharov@oracle.com
author jwilhelm
date Wed, 03 Sep 2014 09:23:58 +0200
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children b1266b08b994
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20380:9337d0e7ea4f 20381:09e9e5240710
1 /*
2 * Copyright (c) 2014, 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 TestHumongousShrinkHeap
26 * @bug 8036025
27 * @summary Verify that heap shrinks after GC in the presence of fragmentation due to humongous objects
28 * @library /testlibrary
29 * @run main/othervm -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=50 -XX:+UseG1GC -XX:G1HeapRegionSize=1M -verbose:gc TestHumongousShrinkHeap
30 */
31
32 import java.lang.management.ManagementFactory;
33 import java.lang.management.MemoryUsage;
34 import java.util.ArrayList;
35 import java.util.List;
36 import sun.management.ManagementFactoryHelper;
37 import static com.oracle.java.testlibrary.Asserts.*;
38
39 public class TestHumongousShrinkHeap {
40
41 public static final String MIN_FREE_RATIO_FLAG_NAME = "MinHeapFreeRatio";
42 public static final String MAX_FREE_RATIO_FLAG_NAME = "MaxHeapFreeRatio";
43
44 private static final ArrayList<ArrayList<byte[]>> garbage = new ArrayList<>();
45 private static final int PAGE_SIZE = 1024 * 1024; // 1M
46 private static final int PAGES_NUM = 5;
47
48
49 public static void main(String[] args) {
50 new TestHumongousShrinkHeap().test();
51 }
52
53 private final void test() {
54 System.gc();
55 MemoryUsagePrinter.printMemoryUsage("init");
56
57 eat();
58 MemoryUsagePrinter.printMemoryUsage("eaten");
59 MemoryUsage muFull = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
60
61 free();
62 MemoryUsagePrinter.printMemoryUsage("free");
63 MemoryUsage muFree = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
64
65 assertLessThan(muFree.getCommitted(), muFull.getCommitted(), String.format(
66 "committed free heap size is not less than committed full heap size, heap hasn't been shrunk?%n"
67 + "%s = %s%n%s = %s",
68 MIN_FREE_RATIO_FLAG_NAME,
69 ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MIN_FREE_RATIO_FLAG_NAME).getValue(),
70 MAX_FREE_RATIO_FLAG_NAME,
71 ManagementFactoryHelper.getDiagnosticMXBean().getVMOption(MAX_FREE_RATIO_FLAG_NAME).getValue()
72 ));
73 }
74
75 private void eat() {
76 int HumongousObjectSize = Math.round(.9f * PAGE_SIZE);
77 System.out.println("Will allocate objects of size=" +
78 MemoryUsagePrinter.humanReadableByteCount(HumongousObjectSize, true));
79
80 for (int i = 0; i < PAGES_NUM; i++) {
81 ArrayList<byte[]> stuff = new ArrayList<>();
82 eatList(stuff, 100, HumongousObjectSize);
83 MemoryUsagePrinter.printMemoryUsage("eat #" + i);
84 garbage.add(stuff);
85 }
86 }
87
88 private void free() {
89 // do not free last one list
90 garbage.subList(0, garbage.size() - 1).clear();
91
92 // do not free last one element from last list
93 ArrayList stuff = garbage.get(garbage.size() - 1);
94 stuff.subList(0, stuff.size() - 1).clear();
95 System.gc();
96 }
97
98 private static void eatList(List garbage, int count, int size) {
99 for (int i = 0; i < count; i++) {
100 garbage.add(new byte[size]);
101 }
102 }
103 }
104
105 /**
106 * Prints memory usage to standard output
107 */
108 class MemoryUsagePrinter {
109
110 public static String humanReadableByteCount(long bytes, boolean si) {
111 int unit = si ? 1000 : 1024;
112 if (bytes < unit) {
113 return bytes + " B";
114 }
115 int exp = (int) (Math.log(bytes) / Math.log(unit));
116 String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1) + (si ? "" : "i");
117 return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
118 }
119
120 public static void printMemoryUsage(String label) {
121 MemoryUsage memusage = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
122 float freeratio = 1f - (float) memusage.getUsed() / memusage.getCommitted();
123 System.out.format("[%-24s] init: %-7s, used: %-7s, comm: %-7s, freeRatio ~= %.1f%%%n",
124 label,
125 humanReadableByteCount(memusage.getInit(), true),
126 humanReadableByteCount(memusage.getUsed(), true),
127 humanReadableByteCount(memusage.getCommitted(), true),
128 freeratio * 100
129 );
130 }
131 }