1 /*
2 * Copyright (c) 2014, 2015, 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 * Common code for string deduplication tests
26 */
27
28 import java.lang.management.*;
29 import java.lang.reflect.*;
30 import java.security.*;
31 import java.util.*;
32 import jdk.test.lib.*;
33 import sun.misc.*;
34
35 class TestStringDeduplicationTools {
36 private static final String YoungGC = "YoungGC";
37 private static final String FullGC = "FullGC";
38
39 private static final int Xmn = 50; // MB
40 private static final int Xms = 100; // MB
41 private static final int Xmx = 100; // MB
42 private static final int MB = 1024 * 1024;
43 private static final int StringLength = 50;
44
45 private static Field valueField;
46 private static Unsafe unsafe;
47 private static byte[] dummy;
48
49 static {
50 try {
51 Field field = Unsafe.class.getDeclaredField("theUnsafe");
52 field.setAccessible(true);
53 unsafe = (Unsafe)field.get(null);
54
55 valueField = String.class.getDeclaredField("value");
56 valueField.setAccessible(true);
57 } catch (Exception e) {
58 throw new RuntimeException(e);
59 }
60 }
61
62 private static Object getValue(String string) {
63 try {
64 return valueField.get(string);
65 } catch (Exception e) {
66 throw new RuntimeException(e);
67 }
68 }
69
70 private static void doFullGc(int numberOfTimes) {
71 for (int i = 0; i < numberOfTimes; i++) {
72 System.out.println("Begin: Full GC " + (i + 1) + "/" + numberOfTimes);
73 System.gc();
74 System.out.println("End: Full GC " + (i + 1) + "/" + numberOfTimes);
75 }
76 }
77
78 private static void doYoungGc(int numberOfTimes) {
79 // Provoke at least numberOfTimes young GCs
80 final int objectSize = 128;
81 final int maxObjectInYoung = (Xmn * MB) / objectSize;
82 for (int i = 0; i < numberOfTimes; i++) {
83 System.out.println("Begin: Young GC " + (i + 1) + "/" + numberOfTimes);
84 for (int j = 0; j < maxObjectInYoung + 1; j++) {
85 dummy = new byte[objectSize];
86 }
87 System.out.println("End: Young GC " + (i + 1) + "/" + numberOfTimes);
88 }
89 }
90
91 private static void forceDeduplication(int ageThreshold, String gcType) {
92 // Force deduplication to happen by either causing a FullGC or a YoungGC.
93 // We do several collections to also provoke a situation where the the
94 // deduplication thread needs to yield while processing the queue. This
95 // also tests that the references in the deduplication queue are adjusted
96 // accordingly.
97 if (gcType.equals(FullGC)) {
98 doFullGc(3);
99 } else {
100 doYoungGc(ageThreshold + 3);
101 }
102 }
103
104 private static String generateString(int id) {
105 StringBuilder builder = new StringBuilder(StringLength);
106
107 builder.append("DeduplicationTestString:" + id + ":");
108
109 while (builder.length() < StringLength) {
110 builder.append('X');
111 }
112
113 return builder.toString();
114 }
115
116 private static ArrayList<String> createStrings(int total, int unique) {
117 System.out.println("Creating strings: total=" + total + ", unique=" + unique);
118 if (total % unique != 0) {
119 throw new RuntimeException("Total must be divisible by unique");
120 }
121
122 ArrayList<String> list = new ArrayList<String>(total);
123 for (int j = 0; j < total / unique; j++) {
124 for (int i = 0; i < unique; i++) {
125 list.add(generateString(i));
126 }
127 }
128
129 return list;
130 }
131
132 /**
133 * Verifies that the given list contains expected number of unique strings.
134 * It's possible that deduplication hasn't completed yet, so the method
135 * will perform several attempts to check with a little pause between.
136 * The method throws RuntimeException to signal that verification failed.
137 *
138 * @param list strings to check
139 * @param uniqueExpected expected number of unique strings
140 * @throws RuntimeException if check fails
141 */
142 private static void verifyStrings(ArrayList<String> list, int uniqueExpected) {
143 boolean passed = false;
144 for (int attempts = 0; attempts < 10; attempts++) {
145 // Check number of deduplicated strings
146 ArrayList<Object> unique = new ArrayList<Object>(uniqueExpected);
147 for (String string: list) {
148 Object value = getValue(string);
149 boolean uniqueValue = true;
150 for (Object obj: unique) {
151 if (obj == value) {
152 uniqueValue = false;
153 break;
154 }
155 }
156
157 if (uniqueValue) {
158 unique.add(value);
159 }
160 }
161
162 System.out.println("Verifying strings: total=" + list.size() +
163 ", uniqueFound=" + unique.size() +
164 ", uniqueExpected=" + uniqueExpected);
165
166 if (unique.size() == uniqueExpected) {
167 System.out.println("Deduplication completed (as fast as " + attempts + " iterations)");
168 passed = true;
169 break;
170 } else {
171 System.out.println("Deduplication not completed, waiting...");
172 // Give the deduplication thread time to complete
173 try {
174 Thread.sleep(1000);
175 } catch (Exception e) {
176 throw new RuntimeException(e);
177 }
178 }
179 }
180 if (!passed) {
181 throw new RuntimeException("String verification failed");
182 }
183 }
184
185 private static OutputAnalyzer runTest(String... extraArgs) throws Exception {
186 String[] defaultArgs = new String[] {
187 "-Xmn" + Xmn + "m",
188 "-Xms" + Xms + "m",
189 "-Xmx" + Xmx + "m",
190 "-XX:+UseG1GC",
191 "-XX:+UnlockDiagnosticVMOptions",
192 "-XX:+VerifyAfterGC" // Always verify after GC
193 };
194
195 ArrayList<String> args = new ArrayList<String>();
196 args.addAll(Arrays.asList(defaultArgs));
197 args.addAll(Arrays.asList(extraArgs));
198
199 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args.toArray(new String[args.size()]));
200 OutputAnalyzer output = new OutputAnalyzer(pb.start());
201 System.err.println(output.getStderr());
202 System.out.println(output.getStdout());
203 return output;
204 }
205
206 private static class DeduplicationTest {
207 public static void main(String[] args) {
208 System.out.println("Begin: DeduplicationTest");
209
210 final int numberOfStrings = Integer.parseUnsignedInt(args[0]);
211 final int numberOfUniqueStrings = Integer.parseUnsignedInt(args[1]);
212 final int ageThreshold = Integer.parseUnsignedInt(args[2]);
213 final String gcType = args[3];
214
215 ArrayList<String> list = createStrings(numberOfStrings, numberOfUniqueStrings);
216 forceDeduplication(ageThreshold, gcType);
217 verifyStrings(list, numberOfUniqueStrings);
218
219 System.out.println("End: DeduplicationTest");
220 }
221
222 public static OutputAnalyzer run(int numberOfStrings, int ageThreshold, String gcType, String... extraArgs) throws Exception {
223 String[] defaultArgs = new String[] {
224 "-XX:+UseStringDeduplication",
225 "-XX:StringDeduplicationAgeThreshold=" + ageThreshold,
226 DeduplicationTest.class.getName(),
227 "" + numberOfStrings,
228 "" + numberOfStrings / 2,
229 "" + ageThreshold,
230 gcType
231 };
232
233 ArrayList<String> args = new ArrayList<String>();
234 args.addAll(Arrays.asList(extraArgs));
235 args.addAll(Arrays.asList(defaultArgs));
236
237 return runTest(args.toArray(new String[args.size()]));
238 }
239 }
240
241 private static class InternedTest {
242 public static void main(String[] args) {
243 // This test verifies that interned strings are always
244 // deduplicated when being interned, and never after
245 // being interned.
246
247 System.out.println("Begin: InternedTest");
248
249 final int ageThreshold = Integer.parseUnsignedInt(args[0]);
250 final String baseString = "DeduplicationTestString:" + InternedTest.class.getName();
251
252 // Create duplicate of baseString
253 StringBuilder sb1 = new StringBuilder(baseString);
254 String dupString1 = sb1.toString();
255 if (getValue(dupString1) == getValue(baseString)) {
256 throw new RuntimeException("Values should not match");
257 }
258
259 // Force baseString to be inspected for deduplication
260 // and be inserted into the deduplication hashtable.
261 forceDeduplication(ageThreshold, FullGC);
262
263 // Wait for deduplication to occur
264 for (int attempts = 0; attempts < 10; attempts++) {
265 if (getValue(dupString1) == getValue(baseString)) {
266 break;
267 }
268 System.out.println("Waiting...");
269 try {
270 Thread.sleep(1000);
271 } catch (Exception e) {
272 throw new RuntimeException(e);
273 }
274 }
275 if (getValue(dupString1) != getValue(baseString)) {
276 throw new RuntimeException("Deduplication has not occurred");
277 }
278
279 // Create a new duplicate of baseString
280 StringBuilder sb2 = new StringBuilder(baseString);
281 String dupString2 = sb2.toString();
282 if (getValue(dupString2) == getValue(baseString)) {
283 throw new RuntimeException("Values should not match");
284 }
285
286 // Intern the new duplicate
287 Object beforeInternedValue = getValue(dupString2);
288 String internedString = dupString2.intern();
289 if (internedString != dupString2) {
290 throw new RuntimeException("String should match");
291 }
292 if (getValue(internedString) != getValue(baseString)) {
293 throw new RuntimeException("Values should match");
294 }
295
296 // Check original value of interned string, to make sure
297 // deduplication happened on the interned string and not
298 // on the base string
299 if (beforeInternedValue == getValue(baseString)) {
300 throw new RuntimeException("Values should not match");
301 }
302
303 System.out.println("End: InternedTest");
304 }
305
306 public static OutputAnalyzer run() throws Exception {
307 return runTest("-Xlog:gc=debug,gc+stringdedup=trace",
308 "-XX:+UseStringDeduplication",
309 "-XX:StringDeduplicationAgeThreshold=" + DefaultAgeThreshold,
310 InternedTest.class.getName(),
311 "" + DefaultAgeThreshold);
312 }
313 }
314
315 /*
316 * Tests
317 */
318
319 private static final int LargeNumberOfStrings = 10000;
320 private static final int SmallNumberOfStrings = 10;
321
322 private static final int MaxAgeThreshold = 15;
323 private static final int DefaultAgeThreshold = 3;
324 private static final int MinAgeThreshold = 1;
325
326 private static final int TooLowAgeThreshold = MinAgeThreshold - 1;
327 private static final int TooHighAgeThreshold = MaxAgeThreshold + 1;
328
329 public static void testYoungGC() throws Exception {
330 // Do young GC to age strings to provoke deduplication
331 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
332 DefaultAgeThreshold,
333 YoungGC,
334 "-Xlog:gc,gc+stringdedup=trace");
335 output.shouldNotContain("Full GC");
336 output.shouldContain("Pause Young (G1 Evacuation Pause)");
337 output.shouldContain("Concurrent String Deduplication");
338 output.shouldContain("Deduplicated:");
339 output.shouldHaveExitValue(0);
340 }
341
342 public static void testFullGC() throws Exception {
343 // Do full GC to age strings to provoke deduplication
344 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
345 DefaultAgeThreshold,
346 FullGC,
347 "-Xlog:gc,gc+stringdedup=trace");
348 output.shouldNotContain("Pause Young (G1 Evacuation Pause)");
349 output.shouldContain("Full GC");
350 output.shouldContain("Concurrent String Deduplication");
351 output.shouldContain("Deduplicated:");
352 output.shouldHaveExitValue(0);
353 }
354
355 public static void testTableResize() throws Exception {
356 // Test with StringDeduplicationResizeALot
357 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
358 DefaultAgeThreshold,
359 YoungGC,
360 "-Xlog:gc,gc+stringdedup=trace",
361 "-XX:+StringDeduplicationResizeALot");
362 output.shouldContain("Concurrent String Deduplication");
363 output.shouldContain("Deduplicated:");
364 output.shouldNotContain("Resize Count: 0");
365 output.shouldHaveExitValue(0);
366 }
367
368 public static void testTableRehash() throws Exception {
369 // Test with StringDeduplicationRehashALot
370 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings,
371 DefaultAgeThreshold,
372 YoungGC,
373 "-Xlog:gc,gc+stringdedup=trace",
374 "-XX:+StringDeduplicationRehashALot");
375 output.shouldContain("Concurrent String Deduplication");
376 output.shouldContain("Deduplicated:");
377 output.shouldNotContain("Rehash Count: 0");
378 output.shouldNotContain("Hash Seed: 0x0");
379 output.shouldHaveExitValue(0);
380 }
381
382 public static void testAgeThreshold() throws Exception {
383 OutputAnalyzer output;
384
385 // Test with max age theshold
386 output = DeduplicationTest.run(SmallNumberOfStrings,
387 MaxAgeThreshold,
388 YoungGC,
389 "-Xlog:gc,gc+stringdedup=trace");
390 output.shouldContain("Concurrent String Deduplication");
391 output.shouldContain("Deduplicated:");
392 output.shouldHaveExitValue(0);
393
394 // Test with min age theshold
395 output = DeduplicationTest.run(SmallNumberOfStrings,
396 MinAgeThreshold,
397 YoungGC,
398 "-Xlog:gc,gc+stringdedup=trace");
399 output.shouldContain("Concurrent String Deduplication");
400 output.shouldContain("Deduplicated:");
401 output.shouldHaveExitValue(0);
402
403 // Test with too low age threshold
404 output = DeduplicationTest.run(SmallNumberOfStrings,
405 TooLowAgeThreshold,
406 YoungGC);
407 output.shouldContain("outside the allowed range");
408 output.shouldHaveExitValue(1);
409
410 // Test with too high age threshold
411 output = DeduplicationTest.run(SmallNumberOfStrings,
412 TooHighAgeThreshold,
413 YoungGC);
414 output.shouldContain("outside the allowed range");
415 output.shouldHaveExitValue(1);
416 }
417
418 public static void testPrintOptions() throws Exception {
419 OutputAnalyzer output;
420
421 // Test without -Xlog:gc
422 output = DeduplicationTest.run(SmallNumberOfStrings,
423 DefaultAgeThreshold,
424 YoungGC);
425 output.shouldNotContain("Concurrent String Deduplication");
426 output.shouldNotContain("Deduplicated:");
427 output.shouldHaveExitValue(0);
428
429 // Test with -Xlog:gc+stringdedup
430 output = DeduplicationTest.run(SmallNumberOfStrings,
431 DefaultAgeThreshold,
432 YoungGC,
433 "-Xlog:gc+stringdedup");
434 output.shouldContain("Concurrent String Deduplication");
435 output.shouldNotContain("Deduplicated:");
436 output.shouldHaveExitValue(0);
437 }
438
439 public static void testInterned() throws Exception {
440 // Test that interned strings are deduplicated before being interned
441 OutputAnalyzer output = InternedTest.run();
442 output.shouldHaveExitValue(0);
443 }
444 }