1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 /*
27 * @test id=passive
28 * @summary Test Shenandoah string deduplication implementation
29 * @key randomness
30 * @requires vm.gc.Shenandoah
31 * @library /test/lib
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 id=generational
48 * @summary Test Shenandoah string deduplication implementation
49 * @key randomness
50 * @requires vm.gc.Shenandoah
51 * @library /test/lib
52 * @modules java.base/java.lang:open
53 * java.management
54 *
55 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
56 * -XX:+UseShenandoahGC -XX:ShenandoahGCMode=generational
57 * -XX:+ShenandoahDegeneratedGC
58 * -DtargetStrings=3000000
59 * TestStringDedupStress
60 */
61
62 /*
63 * @test id=default
64 * @summary Test Shenandoah string deduplication implementation
65 * @key randomness
66 * @requires vm.gc.Shenandoah
67 * @library /test/lib
68 * @modules java.base/java.lang:open
69 * java.management
70 *
71 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
72 * -XX:+UseShenandoahGC
73 * -DtargetStrings=3000000
74 * TestStringDedupStress
75 *
76 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
77 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
78 * -DtargetStrings=2000000
79 * TestStringDedupStress
80 *
81 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
82 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
83 * -XX:+ShenandoahOOMDuringEvacALot
84 * -DtargetStrings=2000000
85 * TestStringDedupStress
86 *
87 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
88 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact
89 * TestStringDedupStress
90 */
91
92 import java.lang.management.*;
93 import java.lang.reflect.*;
94 import java.util.*;
95 import jdk.test.lib.Utils;
96
97 public class TestStringDedupStress {
98 private static Field valueField;
99
100 private static final int TARGET_STRINGS = Integer.getInteger("targetStrings", 2_500_000);
101 private static final long MAX_REWRITE_GC_CYCLES = 6;
102 private static final long MAX_REWRITE_TIME_NS = 30L * 1_000_000_000L; // 30s in ns
103
104 private static final int UNIQUE_STRINGS = 20;
105
106 static {
107 try {
108 valueField = String.class.getDeclaredField("value");
109 valueField.setAccessible(true);
110 } catch (Exception e) {
111 throw new RuntimeException(e);
112 }
113 }
114
115 private static Object getValue(String string) {
116 try {
117 return valueField.get(string);
118 } catch (Exception e) {
119 throw new RuntimeException(e);
120 }
121 }
122
123 static class StringAndId {
124 private String str;
125 private int id;
126
127 public StringAndId(String str, int id) {
128 this.str = str;
129 this.id = id;
130 }
131
132 public String str() {
133 return str;
134 }
135
136 public int id() {
137 return id;
138 }
139 }
140
141 // Generate uniqueStrings number of strings
142 private static void generateStrings(ArrayList<StringAndId> strs, int uniqueStrings) {
143 Random rn = Utils.getRandomInstance();
144 for (int u = 0; u < uniqueStrings; u++) {
145 int n = rn.nextInt(uniqueStrings);
146 strs.add(new StringAndId("Unique String " + n, n));
147 }
148 }
149
150 private static int verifyDedupString(ArrayList<StringAndId> strs) {
151 Map<Object, StringAndId> seen = new HashMap<>(TARGET_STRINGS*2);
152 int total = 0;
153 int dedup = 0;
154
155 for (StringAndId item : strs) {
156 total++;
157 StringAndId existingItem = seen.get(getValue(item.str()));
158 if (existingItem == null) {
159 seen.put(getValue(item.str()), item);
160 } else {
161 if (item.id() != existingItem.id() ||
162 !item.str().equals(existingItem.str())) {
163 System.out.println("StringDedup error:");
164 System.out.println("id: " + item.id() + " != " + existingItem.id());
165 System.out.println("or String: " + item.str() + " != " + existingItem.str());
166 throw new RuntimeException("StringDedup Test failed");
167 } else {
168 dedup++;
169 }
170 }
171 }
172 System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));
173 return (total - dedup);
174 }
175
176 static volatile ArrayList<StringAndId> astrs = new ArrayList<>();
177 static GarbageCollectorMXBean gcCycleMBean;
178
179 public static void main(String[] args) {
180 Random rn = Utils.getRandomInstance();
181
182 for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
183 if ("Shenandoah Cycles".equals(bean.getName())) {
184 gcCycleMBean = bean;
185 break;
186 }
187 }
188
189 if (gcCycleMBean == null) {
190 throw new RuntimeException("Can not find Shenandoah GC cycle mbean");
191 }
192
193 // Generate roughly TARGET_STRINGS strings, only UNIQUE_STRINGS are unique
194 int genIters = TARGET_STRINGS / UNIQUE_STRINGS;
195 for (int index = 0; index < genIters; index++) {
196 generateStrings(astrs, UNIQUE_STRINGS);
197 }
198
199 long cycleBeforeRewrite = gcCycleMBean.getCollectionCount();
200 long timeBeforeRewriteNanos = System.nanoTime();
201
202 long loop = 1;
203 while (true) {
204 int arrSize = astrs.size();
205 int index = rn.nextInt(arrSize);
206 StringAndId item = astrs.get(index);
207 int n = rn.nextInt(UNIQUE_STRINGS);
208 item.str = "Unique String " + n;
209 item.id = n;
210
211 if (loop++ % 1000 == 0) {
212 // enough GC cycles for rewritten strings to be deduplicated
213 if (gcCycleMBean.getCollectionCount() - cycleBeforeRewrite >= MAX_REWRITE_GC_CYCLES) {
214 break;
215 }
216
217 // enough time is spent waiting for GC to happen
218 if (System.nanoTime() - timeBeforeRewriteNanos >= MAX_REWRITE_TIME_NS) {
219 break;
220 }
221 }
222 }
223 verifyDedupString(astrs);
224 }
225 }