1 /*
2 * Copyright (c) 2017, 2018, Red Hat, Inc. 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 /*
26 * @test TestStringDedupStress
27 * @summary Test Shenandoah string deduplication implementation
28 * @key gc
29 * @requires vm.gc.Shenandoah & !vm.graal.enabled
30 * @library /test/lib
31 * @modules java.base/jdk.internal.misc:open
32 * @modules java.base/java.lang:open
33 * java.management
34 *
35 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
36 * -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive
37 * -XX:+ShenandoahDegeneratedGC
38 * TestStringDedupStress
39 *
40 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
41 * -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive
42 * -XX:-ShenandoahDegeneratedGC
43 * TestStringDedupStress
44 */
45
46 /*
47 * @test TestStringDedupStress
48 * @summary Test Shenandoah string deduplication implementation
49 * @key gc
50 * @requires vm.gc.Shenandoah & !vm.graal.enabled
51 * @library /test/lib
52 * @modules java.base/jdk.internal.misc:open
53 * @modules java.base/java.lang:open
54 * java.management
55 *
56 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
57 * -XX:+UseShenandoahGC
58 * -DtargetStrings=3000000
59 * TestStringDedupStress
60 *
61 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
62 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
63 * -DtargetStrings=2000000
64 * TestStringDedupStress
65 *
66 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
67 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
68 * -XX:+ShenandoahOOMDuringEvacALot
69 * -DtargetStrings=2000000
70 * TestStringDedupStress
71 *
72 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
73 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact
74 * TestStringDedupStress
75 */
76
77 import java.lang.management.*;
78 import java.lang.reflect.*;
79 import java.util.*;
80
81 import sun.misc.*;
82
83 public class TestStringDedupStress {
84 private static Field valueField;
85 private static Unsafe unsafe;
86
87 private static final int TARGET_STRINGS = Integer.getInteger("targetStrings", 2_500_000);
88 private static final long MAX_REWRITE_GC_CYCLES = 6;
89 private static final long MAX_REWRITE_TIME = 30*1000; // ms
90
91 private static final int UNIQUE_STRINGS = 20;
92
93 static {
94 try {
95 Field field = Unsafe.class.getDeclaredField("theUnsafe");
96 field.setAccessible(true);
97 unsafe = (Unsafe) field.get(null);
98
99 valueField = String.class.getDeclaredField("value");
100 valueField.setAccessible(true);
101 } catch (Exception e) {
102 throw new RuntimeException(e);
103 }
104 }
105
106 private static Object getValue(String string) {
107 try {
108 return valueField.get(string);
109 } catch (Exception e) {
110 throw new RuntimeException(e);
111 }
112 }
113
114 static class StringAndId {
115 private String str;
116 private int id;
117
118 public StringAndId(String str, int id) {
119 this.str = str;
120 this.id = id;
121 }
122
123 public String str() {
124 return str;
125 }
126
127 public int id() {
128 return id;
129 }
130 }
131
132 // Generate uniqueStrings number of strings
133 private static void generateStrings(ArrayList<StringAndId> strs, int uniqueStrings) {
134 Random rn = new Random();
135 for (int u = 0; u < uniqueStrings; u++) {
136 int n = rn.nextInt(uniqueStrings);
137 strs.add(new StringAndId("Unique String " + n, n));
138 }
139 }
140
141 private static int verifyDedupString(ArrayList<StringAndId> strs) {
142 Map<Object, StringAndId> seen = new HashMap<>(TARGET_STRINGS*2);
143 int total = 0;
144 int dedup = 0;
145
146 for (StringAndId item : strs) {
147 total++;
148 StringAndId existingItem = seen.get(getValue(item.str()));
149 if (existingItem == null) {
150 seen.put(getValue(item.str()), item);
151 } else {
152 if (item.id() != existingItem.id() ||
153 !item.str().equals(existingItem.str())) {
154 System.out.println("StringDedup error:");
155 System.out.println("id: " + item.id() + " != " + existingItem.id());
156 System.out.println("or String: " + item.str() + " != " + existingItem.str());
157 throw new RuntimeException("StringDedup Test failed");
158 } else {
159 dedup++;
160 }
161 }
162 }
163 System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));
164 return (total - dedup);
165 }
166
167 static volatile ArrayList<StringAndId> astrs = new ArrayList<>();
168 static GarbageCollectorMXBean gcCycleMBean;
169
170 public static void main(String[] args) {
171 Random rn = new Random();
172
173 for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
174 if ("Shenandoah Cycles".equals(bean.getName())) {
175 gcCycleMBean = bean;
176 break;
177 }
178 }
179
180 if (gcCycleMBean == null) {
181 throw new RuntimeException("Can not find Shenandoah GC cycle mbean");
182 }
183
184 // Generate roughly TARGET_STRINGS strings, only UNIQUE_STRINGS are unique
185 int genIters = TARGET_STRINGS / UNIQUE_STRINGS;
186 for (int index = 0; index < genIters; index++) {
187 generateStrings(astrs, UNIQUE_STRINGS);
188 }
189
190 long cycleBeforeRewrite = gcCycleMBean.getCollectionCount();
191 long timeBeforeRewrite = System.currentTimeMillis();
192
193 long loop = 1;
194 while (true) {
195 int arrSize = astrs.size();
196 int index = rn.nextInt(arrSize);
197 StringAndId item = astrs.get(index);
198 int n = rn.nextInt(UNIQUE_STRINGS);
199 item.str = "Unique String " + n;
200 item.id = n;
201
202 if (loop++ % 1000 == 0) {
203 // enough GC cycles for rewritten strings to be deduplicated
204 if (gcCycleMBean.getCollectionCount() - cycleBeforeRewrite >= MAX_REWRITE_GC_CYCLES) {
205 break;
206 }
207
208 // enough time is spent waiting for GC to happen
209 if (System.currentTimeMillis() - timeBeforeRewrite >= MAX_REWRITE_TIME) {
210 break;
211 }
212 }
213 }
214 verifyDedupString(astrs);
215 }
216 }