1 /*
2 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 /*
25 * @test TestStringDedupStress
26 * @summary Test Shenandoah string deduplication implementation
27 * @key gc
28 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
29 * -verbose:gc
30 * -DtargetStrings=3000000
31 * TestStringDedupStress
32 *
33 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
34 * -XX:ShenandoahGCHeuristics=aggressive -DtargetStrings=2000000
35 * -verbose:gc
36 * TestStringDedupStress
37 *
38 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
39 * -XX:ShenandoahGCHeuristics=aggressive -XX:+ShenandoahOOMDuringEvacALot -DtargetStrings=2000000
40 * -verbose:gc
41 * TestStringDedupStress
42 *
43 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
44 * -XX:ShenandoahGCHeuristics=static -DtargetStrings=4000000
45 * -verbose:gc
46 * TestStringDedupStress
47 *
48 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
49 * -XX:ShenandoahGCHeuristics=compact
50 * -verbose:gc
51 * TestStringDedupStress
52 *
53 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
54 * -XX:ShenandoahGCMode=passive -XX:+ShenandoahDegeneratedGC -DtargetOverwrites=40000000
55 * -verbose:gc
56 * TestStringDedupStress
57 *
58 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
59 * -XX:ShenandoahGCMode=passive -XX:-ShenandoahDegeneratedGC -DtargetOverwrites=40000000
60 * -verbose:gc
61 * TestStringDedupStress
62 *
63 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
64 * -XX:ShenandoahUpdateRefsEarly=off -DtargetStrings=3000000
65 * -verbose:gc
66 * TestStringDedupStress
67 *
68 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
69 * -XX:ShenandoahGCHeuristics=compact -XX:ShenandoahUpdateRefsEarly=off -DtargetStrings=2000000
70 * -verbose:gc
71 * TestStringDedupStress
72 *
73 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
74 * -XX:ShenandoahGCHeuristics=aggressive -XX:ShenandoahUpdateRefsEarly=off -DtargetStrings=2000000
75 * -verbose:gc
76 * TestStringDedupStress
77 *
78 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
79 * -XX:ShenandoahGCHeuristics=static -XX:ShenandoahUpdateRefsEarly=off -DtargetOverwrites=4000000
80 * -verbose:gc
81 * TestStringDedupStress
82 *
83 * @run main/othervm -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:+UseStringDeduplication -Xmx1g
84 * -XX:ShenandoahGCHeuristics=aggressive -XX:ShenandoahUpdateRefsEarly=off -XX:+ShenandoahOOMDuringEvacALot -DtargetStrings=2000000
85 * -verbose:gc
86 * TestStringDedupStress
87 */
88
89 import java.lang.management.*;
90 import java.lang.reflect.*;
91 import java.util.*;
92
93 import sun.misc.*;
94
95 public class TestStringDedupStress {
96 private static Field valueField;
97 private static Unsafe unsafe;
98
99 private static final int TARGET_STRINGS = Integer.getInteger("targetStrings", 2_500_000);
100 private static final long MAX_REWRITE_GC_CYCLES = 6;
101 private static final long MAX_REWRITE_TIME = 30*1000; // ms
102
103 private static final int UNIQUE_STRINGS = 20;
104
105 static {
106 try {
107 Field field = Unsafe.class.getDeclaredField("theUnsafe");
108 field.setAccessible(true);
109 unsafe = (Unsafe) field.get(null);
110
111 valueField = String.class.getDeclaredField("value");
112 valueField.setAccessible(true);
113 } catch (Exception e) {
114 throw new RuntimeException(e);
115 }
116 }
117
118 private static Object getValue(String string) {
119 try {
120 return valueField.get(string);
121 } catch (Exception e) {
122 throw new RuntimeException(e);
123 }
124 }
125
126 static class StringAndId {
127 private String str;
128 private int id;
129
130 public StringAndId(String str, int id) {
131 this.str = str;
132 this.id = id;
133 }
134
135 public String str() {
136 return str;
137 }
138
139 public int id() {
140 return id;
141 }
142 }
143
144 // Generate uniqueStrings number of strings
145 private static void generateStrings(ArrayList<StringAndId> strs, int uniqueStrings) {
146 Random rn = new Random();
147 for (int u = 0; u < uniqueStrings; u++) {
148 int n = rn.nextInt(uniqueStrings);
149 strs.add(new StringAndId("Unique String " + n, n));
150 }
151 }
152
153 private static int verifyDedupString(ArrayList<StringAndId> strs) {
154 Map<Object, StringAndId> seen = new HashMap<>(TARGET_STRINGS*2);
155 int total = 0;
156 int dedup = 0;
157
158 for (StringAndId item : strs) {
159 total++;
160 StringAndId existingItem = seen.get(getValue(item.str()));
161 if (existingItem == null) {
162 seen.put(getValue(item.str()), item);
163 } else {
164 if (item.id() != existingItem.id() ||
165 !item.str().equals(existingItem.str())) {
166 System.out.println("StringDedup error:");
167 System.out.println("id: " + item.id() + " != " + existingItem.id());
168 System.out.println("or String: " + item.str() + " != " + existingItem.str());
169 throw new RuntimeException("StringDedup Test failed");
170 } else {
171 dedup++;
172 }
173 }
174 }
175 System.out.println("Dedup: " + dedup + "/" + total + " unique: " + (total - dedup));
176 return (total - dedup);
177 }
178
179 static volatile ArrayList<StringAndId> astrs = new ArrayList<>();
180 static GarbageCollectorMXBean gcCycleMBean;
181
182 public static void main(String[] args) {
183 Random rn = new Random();
184
185 for (GarbageCollectorMXBean bean : ManagementFactory.getGarbageCollectorMXBeans()) {
186 if ("Shenandoah Cycles".equals(bean.getName())) {
187 gcCycleMBean = bean;
188 break;
189 }
190 }
191
192 if (gcCycleMBean == null) {
193 throw new RuntimeException("Can not find Shenandoah GC cycle mbean");
194 }
195
196 // Generate roughly TARGET_STRINGS strings, only UNIQUE_STRINGS are unique
197 int genIters = TARGET_STRINGS / UNIQUE_STRINGS;
198 for (int index = 0; index < genIters; index++) {
199 generateStrings(astrs, UNIQUE_STRINGS);
200 }
201
202 long cycleBeforeRewrite = gcCycleMBean.getCollectionCount();
203 long timeBeforeRewrite = System.currentTimeMillis();
204
205 long loop = 1;
206 while (true) {
207 int arrSize = astrs.size();
208 int index = rn.nextInt(arrSize);
209 StringAndId item = astrs.get(index);
210 int n = rn.nextInt(UNIQUE_STRINGS);
211 item.str = "Unique String " + n;
212 item.id = n;
213
214 if (loop++ % 1000 == 0) {
215 // enough GC cycles for rewritten strings to be deduplicated
216 if (gcCycleMBean.getCollectionCount() - cycleBeforeRewrite >= MAX_REWRITE_GC_CYCLES) {
217 break;
218 }
219
220 // enough time is spent waiting for GC to happen
221 if (System.currentTimeMillis() - timeBeforeRewrite >= MAX_REWRITE_TIME) {
222 break;
223 }
224 }
225 }
226 verifyDedupString(astrs);
227 }
228 }