1 /*
2 * Copyright (c) 2017, 2021, 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 id=passive
27 * @summary Test Shenandoah string deduplication implementation
28 * @key randomness
29 * @requires vm.gc.Shenandoah
30 * @library /test/lib
31 * @modules java.base/java.lang:open
32 * java.management
33 *
34 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
35 * -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive
36 * -XX:+ShenandoahDegeneratedGC
37 * TestStringDedupStress
38 *
39 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
40 * -XX:+UseShenandoahGC -XX:ShenandoahGCMode=passive
41 * -XX:-ShenandoahDegeneratedGC
42 * TestStringDedupStress
43 */
44
45 /*
46 * @test id=default
47 * @summary Test Shenandoah string deduplication implementation
48 * @key randomness
49 * @requires vm.gc.Shenandoah
50 * @library /test/lib
51 * @modules java.base/java.lang:open
52 * java.management
53 *
54 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
55 * -XX:+UseShenandoahGC
56 * -DtargetStrings=3000000
57 * TestStringDedupStress
58 *
59 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
60 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
61 * -DtargetStrings=2000000
62 * TestStringDedupStress
63 *
64 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
65 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=aggressive
66 * -XX:+ShenandoahOOMDuringEvacALot
67 * -DtargetStrings=2000000
68 * TestStringDedupStress
69 *
70 * @run main/othervm -Xmx1g -Xlog:gc+stats -Xlog:gc -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseStringDeduplication
71 * -XX:+UseShenandoahGC -XX:ShenandoahGCHeuristics=compact
72 * TestStringDedupStress
73 */
74
75 import java.lang.management.*;
76 import java.lang.reflect.*;
77 import java.util.*;
78 import jdk.test.lib.Utils;
79
80 public class TestStringDedupStress {
81 private static Field valueField;
82
83 private static final int TARGET_STRINGS = Integer.getInteger("targetStrings", 2_500_000);
84 private static final long MAX_REWRITE_GC_CYCLES = 6;
85 private static final long MAX_REWRITE_TIME_NS = 30L * 1_000_000_000L; // 30s in ns
86
87 private static final int UNIQUE_STRINGS = 20;
88
89 static {
90 try {
91 valueField = String.class.getDeclaredField("value");
92 valueField.setAccessible(true);
93 } catch (Exception e) {
94 throw new RuntimeException(e);
95 }
96 }
97
98 private static Object getValue(String string) {
99 try {
100 return valueField.get(string);
101 } catch (Exception e) {
102 throw new RuntimeException(e);
103 }
104 }
105
106 static class StringAndId {
107 private String str;
108 private int id;
109
110 public StringAndId(String str, int id) {
111 this.str = str;
112 this.id = id;
113 }
114
115 public String str() {
116 return str;
117 }
118
119 public int id() {
120 return id;
121 }
122 }
123
124 // Generate uniqueStrings number of strings
125 private static void generateStrings(ArrayList<StringAndId> strs, int uniqueStrings) {
126 Random rn = Utils.getRandomInstance();
127 for (int u = 0; u < uniqueStrings; u++) {
128 int n = rn.nextInt(uniqueStrings);
129 strs.add(new StringAndId("Unique String " + n, n));
130 }
131 }
132
133 private static int verifyDedupString(ArrayList<StringAndId> strs) {
134 Map<Object, StringAndId> seen = new HashMap<>(TARGET_STRINGS*2);
135 int total = 0;
136 int dedup = 0;
137
138 for (StringAndId item : strs) {
139 total++;
140 StringAndId existingItem = seen.get(getValue(item.str()));
141 if (existingItem == null) {
142 seen.put(getValue(item.str()), item);
143 } else {
144 if (item.id() != existingItem.id() ||
145 !item.str().equals(existingItem.str())) {
146 System.out.println("StringDedup error:");
147 System.out.println("id: " + item.id() + " != " + existingItem.id());
148 System.out.println("or String: " + item.str() + " != " + existingItem.str());
149 throw new RuntimeException("StringDedup Test failed");
150 } else {
151 dedup++;
152 }
153 }
154 }
155 System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));
156 return (total - dedup);
157 }
158
159 static volatile ArrayList<StringAndId> astrs = new ArrayList<>();
160 static GarbageCollectorMXBean gcCycleMBean;
161
162 public static void main(String[] args) {
163 Random rn = Utils.getRandomInstance();
164
165 for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
166 if ("Shenandoah Cycles".equals(bean.getName())) {
167 gcCycleMBean = bean;
168 break;
169 }
170 }
171
172 if (gcCycleMBean == null) {
173 throw new RuntimeException("Can not find Shenandoah GC cycle mbean");
174 }
175
176 // Generate roughly TARGET_STRINGS strings, only UNIQUE_STRINGS are unique
177 int genIters = TARGET_STRINGS / UNIQUE_STRINGS;
178 for (int index = 0; index < genIters; index++) {
179 generateStrings(astrs, UNIQUE_STRINGS);
180 }
181
182 long cycleBeforeRewrite = gcCycleMBean.getCollectionCount();
183 long timeBeforeRewriteNanos = System.nanoTime();
184
185 long loop = 1;
186 while (true) {
187 int arrSize = astrs.size();
188 int index = rn.nextInt(arrSize);
189 StringAndId item = astrs.get(index);
190 int n = rn.nextInt(UNIQUE_STRINGS);
191 item.str = "Unique String " + n;
192 item.id = n;
193
194 if (loop++ % 1000 == 0) {
195 // enough GC cycles for rewritten strings to be deduplicated
196 if (gcCycleMBean.getCollectionCount() - cycleBeforeRewrite >= MAX_REWRITE_GC_CYCLES) {
197 break;
198 }
199
200 // enough time is spent waiting for GC to happen
201 if (System.nanoTime() - timeBeforeRewriteNanos >= MAX_REWRITE_TIME_NS) {
202 break;
203 }
204 }
205 }
206 verifyDedupString(astrs);
207 }
208 }