Mercurial > hg > truffle
comparison test/gc/g1/TestStringDeduplicationTools.java @ 17764:595c0f60d50d
8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp
author | pliden |
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date | Tue, 18 Mar 2014 19:07:22 +0100 |
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children | fd8ddf2d2f6b |
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1 /* | |
2 * Copyright (c) 2014, 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 com.oracle.java.testlibrary.*; | |
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 private static void verifyStrings(ArrayList<String> list, int uniqueExpected) { | |
133 for (;;) { | |
134 // Check number of deduplicated strings | |
135 ArrayList<Object> unique = new ArrayList<Object>(uniqueExpected); | |
136 for (String string: list) { | |
137 Object value = getValue(string); | |
138 boolean uniqueValue = true; | |
139 for (Object obj: unique) { | |
140 if (obj == value) { | |
141 uniqueValue = false; | |
142 break; | |
143 } | |
144 } | |
145 | |
146 if (uniqueValue) { | |
147 unique.add(value); | |
148 } | |
149 } | |
150 | |
151 System.out.println("Verifying strings: total=" + list.size() + | |
152 ", uniqueFound=" + unique.size() + | |
153 ", uniqueExpected=" + uniqueExpected); | |
154 | |
155 if (unique.size() == uniqueExpected) { | |
156 System.out.println("Deduplication completed"); | |
157 break; | |
158 } else { | |
159 System.out.println("Deduplication not completed, waiting..."); | |
160 | |
161 // Give the deduplication thread time to complete | |
162 try { | |
163 Thread.sleep(1000); | |
164 } catch (Exception e) { | |
165 throw new RuntimeException(e); | |
166 } | |
167 } | |
168 } | |
169 } | |
170 | |
171 private static OutputAnalyzer runTest(String... extraArgs) throws Exception { | |
172 String[] defaultArgs = new String[] { | |
173 "-Xmn" + Xmn + "m", | |
174 "-Xms" + Xms + "m", | |
175 "-Xmx" + Xmx + "m", | |
176 "-XX:+UseG1GC", | |
177 "-XX:+UnlockDiagnosticVMOptions", | |
178 "-XX:+VerifyAfterGC" // Always verify after GC | |
179 }; | |
180 | |
181 ArrayList<String> args = new ArrayList<String>(); | |
182 args.addAll(Arrays.asList(defaultArgs)); | |
183 args.addAll(Arrays.asList(extraArgs)); | |
184 | |
185 ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(args.toArray(new String[args.size()])); | |
186 OutputAnalyzer output = new OutputAnalyzer(pb.start()); | |
187 System.err.println(output.getStderr()); | |
188 System.out.println(output.getStdout()); | |
189 return output; | |
190 } | |
191 | |
192 private static class DeduplicationTest { | |
193 public static void main(String[] args) { | |
194 System.out.println("Begin: DeduplicationTest"); | |
195 | |
196 final int numberOfStrings = Integer.parseUnsignedInt(args[0]); | |
197 final int numberOfUniqueStrings = Integer.parseUnsignedInt(args[1]); | |
198 final int ageThreshold = Integer.parseUnsignedInt(args[2]); | |
199 final String gcType = args[3]; | |
200 | |
201 ArrayList<String> list = createStrings(numberOfStrings, numberOfUniqueStrings); | |
202 forceDeduplication(ageThreshold, gcType); | |
203 verifyStrings(list, numberOfUniqueStrings); | |
204 | |
205 System.out.println("End: DeduplicationTest"); | |
206 } | |
207 | |
208 public static OutputAnalyzer run(int numberOfStrings, int ageThreshold, String gcType, String... extraArgs) throws Exception { | |
209 String[] defaultArgs = new String[] { | |
210 "-XX:+UseStringDeduplication", | |
211 "-XX:StringDeduplicationAgeThreshold=" + ageThreshold, | |
212 DeduplicationTest.class.getName(), | |
213 "" + numberOfStrings, | |
214 "" + numberOfStrings / 2, | |
215 "" + ageThreshold, | |
216 gcType | |
217 }; | |
218 | |
219 ArrayList<String> args = new ArrayList<String>(); | |
220 args.addAll(Arrays.asList(extraArgs)); | |
221 args.addAll(Arrays.asList(defaultArgs)); | |
222 | |
223 return runTest(args.toArray(new String[args.size()])); | |
224 } | |
225 } | |
226 | |
227 private static class InternedTest { | |
228 public static void main(String[] args) { | |
229 // This test verifies that interned strings are always | |
230 // deduplicated when being interned, and never after | |
231 // being interned. | |
232 | |
233 System.out.println("Begin: InternedTest"); | |
234 | |
235 final int ageThreshold = Integer.parseUnsignedInt(args[0]); | |
236 final String baseString = "DeduplicationTestString:" + InternedTest.class.getName(); | |
237 | |
238 // Create duplicate of baseString | |
239 StringBuilder sb1 = new StringBuilder(baseString); | |
240 String dupString1 = sb1.toString(); | |
241 if (getValue(dupString1) == getValue(baseString)) { | |
242 throw new RuntimeException("Values should not match"); | |
243 } | |
244 | |
245 // Force baseString to be inspected for deduplication | |
246 // and be inserted into the deduplication hashtable. | |
247 forceDeduplication(ageThreshold, FullGC); | |
248 | |
249 // Wait for deduplication to occur | |
250 while (getValue(dupString1) != getValue(baseString)) { | |
251 System.out.println("Waiting..."); | |
252 try { | |
253 Thread.sleep(100); | |
254 } catch (Exception e) { | |
255 throw new RuntimeException(e); | |
256 } | |
257 } | |
258 | |
259 // Create a new duplicate of baseString | |
260 StringBuilder sb2 = new StringBuilder(baseString); | |
261 String dupString2 = sb2.toString(); | |
262 if (getValue(dupString2) == getValue(baseString)) { | |
263 throw new RuntimeException("Values should not match"); | |
264 } | |
265 | |
266 // Intern the new duplicate | |
267 Object beforeInternedValue = getValue(dupString2); | |
268 String internedString = dupString2.intern(); | |
269 if (internedString != dupString2) { | |
270 throw new RuntimeException("String should match"); | |
271 } | |
272 if (getValue(internedString) != getValue(baseString)) { | |
273 throw new RuntimeException("Values should match"); | |
274 } | |
275 | |
276 // Check original value of interned string, to make sure | |
277 // deduplication happened on the interned string and not | |
278 // on the base string | |
279 if (beforeInternedValue == getValue(baseString)) { | |
280 throw new RuntimeException("Values should not match"); | |
281 } | |
282 | |
283 System.out.println("End: InternedTest"); | |
284 } | |
285 | |
286 public static OutputAnalyzer run() throws Exception { | |
287 return runTest("-XX:+PrintGC", | |
288 "-XX:+PrintGCDetails", | |
289 "-XX:+UseStringDeduplication", | |
290 "-XX:+PrintStringDeduplicationStatistics", | |
291 "-XX:StringDeduplicationAgeThreshold=" + DefaultAgeThreshold, | |
292 InternedTest.class.getName(), | |
293 "" + DefaultAgeThreshold); | |
294 } | |
295 } | |
296 | |
297 private static class MemoryUsageTest { | |
298 public static void main(String[] args) { | |
299 System.out.println("Begin: MemoryUsageTest"); | |
300 | |
301 final boolean useStringDeduplication = Boolean.parseBoolean(args[0]); | |
302 final int numberOfStrings = LargeNumberOfStrings; | |
303 final int numberOfUniqueStrings = 1; | |
304 | |
305 ArrayList<String> list = createStrings(numberOfStrings, numberOfUniqueStrings); | |
306 forceDeduplication(DefaultAgeThreshold, FullGC); | |
307 | |
308 if (useStringDeduplication) { | |
309 verifyStrings(list, numberOfUniqueStrings); | |
310 } | |
311 | |
312 System.gc(); | |
313 System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed()); | |
314 | |
315 System.out.println("End: MemoryUsageTest"); | |
316 } | |
317 | |
318 public static OutputAnalyzer run(boolean useStringDeduplication) throws Exception { | |
319 String[] extraArgs = new String[0]; | |
320 | |
321 if (useStringDeduplication) { | |
322 extraArgs = new String[] { | |
323 "-XX:+UseStringDeduplication", | |
324 "-XX:+PrintStringDeduplicationStatistics", | |
325 "-XX:StringDeduplicationAgeThreshold=" + DefaultAgeThreshold | |
326 }; | |
327 } | |
328 | |
329 String[] defaultArgs = new String[] { | |
330 "-XX:+PrintGC", | |
331 "-XX:+PrintGCDetails", | |
332 MemoryUsageTest.class.getName(), | |
333 "" + useStringDeduplication | |
334 }; | |
335 | |
336 ArrayList<String> args = new ArrayList<String>(); | |
337 args.addAll(Arrays.asList(extraArgs)); | |
338 args.addAll(Arrays.asList(defaultArgs)); | |
339 | |
340 return runTest(args.toArray(new String[args.size()])); | |
341 } | |
342 } | |
343 | |
344 /* | |
345 * Tests | |
346 */ | |
347 | |
348 private static final int LargeNumberOfStrings = 10000; | |
349 private static final int SmallNumberOfStrings = 10; | |
350 | |
351 private static final int MaxAgeThreshold = 15; | |
352 private static final int DefaultAgeThreshold = 3; | |
353 private static final int MinAgeThreshold = 1; | |
354 | |
355 private static final int TooLowAgeThreshold = MinAgeThreshold - 1; | |
356 private static final int TooHighAgeThreshold = MaxAgeThreshold + 1; | |
357 | |
358 public static void testYoungGC() throws Exception { | |
359 // Do young GC to age strings to provoke deduplication | |
360 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings, | |
361 DefaultAgeThreshold, | |
362 YoungGC, | |
363 "-XX:+PrintGC", | |
364 "-XX:+PrintStringDeduplicationStatistics"); | |
365 output.shouldNotContain("Full GC"); | |
366 output.shouldContain("GC pause (G1 Evacuation Pause) (young)"); | |
367 output.shouldContain("GC concurrent-string-deduplication"); | |
368 output.shouldContain("Deduplicated:"); | |
369 output.shouldHaveExitValue(0); | |
370 } | |
371 | |
372 public static void testFullGC() throws Exception { | |
373 // Do full GC to age strings to provoke deduplication | |
374 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings, | |
375 DefaultAgeThreshold, | |
376 FullGC, | |
377 "-XX:+PrintGC", | |
378 "-XX:+PrintStringDeduplicationStatistics"); | |
379 output.shouldNotContain("GC pause (G1 Evacuation Pause) (young)"); | |
380 output.shouldContain("Full GC"); | |
381 output.shouldContain("GC concurrent-string-deduplication"); | |
382 output.shouldContain("Deduplicated:"); | |
383 output.shouldHaveExitValue(0); | |
384 } | |
385 | |
386 public static void testTableResize() throws Exception { | |
387 // Test with StringDeduplicationResizeALot | |
388 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings, | |
389 DefaultAgeThreshold, | |
390 YoungGC, | |
391 "-XX:+PrintGC", | |
392 "-XX:+PrintStringDeduplicationStatistics", | |
393 "-XX:+StringDeduplicationResizeALot"); | |
394 output.shouldContain("GC concurrent-string-deduplication"); | |
395 output.shouldContain("Deduplicated:"); | |
396 output.shouldNotContain("Resize Count: 0"); | |
397 output.shouldHaveExitValue(0); | |
398 } | |
399 | |
400 public static void testTableRehash() throws Exception { | |
401 // Test with StringDeduplicationRehashALot | |
402 OutputAnalyzer output = DeduplicationTest.run(LargeNumberOfStrings, | |
403 DefaultAgeThreshold, | |
404 YoungGC, | |
405 "-XX:+PrintGC", | |
406 "-XX:+PrintStringDeduplicationStatistics", | |
407 "-XX:+StringDeduplicationRehashALot"); | |
408 output.shouldContain("GC concurrent-string-deduplication"); | |
409 output.shouldContain("Deduplicated:"); | |
410 output.shouldNotContain("Rehash Count: 0"); | |
411 output.shouldNotContain("Hash Seed: 0x0"); | |
412 output.shouldHaveExitValue(0); | |
413 } | |
414 | |
415 public static void testAgeThreshold() throws Exception { | |
416 OutputAnalyzer output; | |
417 | |
418 // Test with max age theshold | |
419 output = DeduplicationTest.run(SmallNumberOfStrings, | |
420 MaxAgeThreshold, | |
421 YoungGC, | |
422 "-XX:+PrintGC", | |
423 "-XX:+PrintStringDeduplicationStatistics"); | |
424 output.shouldContain("GC concurrent-string-deduplication"); | |
425 output.shouldContain("Deduplicated:"); | |
426 output.shouldHaveExitValue(0); | |
427 | |
428 // Test with min age theshold | |
429 output = DeduplicationTest.run(SmallNumberOfStrings, | |
430 MinAgeThreshold, | |
431 YoungGC, | |
432 "-XX:+PrintGC", | |
433 "-XX:+PrintStringDeduplicationStatistics"); | |
434 output.shouldContain("GC concurrent-string-deduplication"); | |
435 output.shouldContain("Deduplicated:"); | |
436 output.shouldHaveExitValue(0); | |
437 | |
438 // Test with too low age threshold | |
439 output = DeduplicationTest.run(SmallNumberOfStrings, | |
440 TooLowAgeThreshold, | |
441 YoungGC); | |
442 output.shouldContain("StringDeduplicationAgeThreshold of " + TooLowAgeThreshold + | |
443 " is invalid; must be between " + MinAgeThreshold + " and " + MaxAgeThreshold); | |
444 output.shouldHaveExitValue(1); | |
445 | |
446 // Test with too high age threshold | |
447 output = DeduplicationTest.run(SmallNumberOfStrings, | |
448 TooHighAgeThreshold, | |
449 YoungGC); | |
450 output.shouldContain("StringDeduplicationAgeThreshold of " + TooHighAgeThreshold + | |
451 " is invalid; must be between " + MinAgeThreshold + " and " + MaxAgeThreshold); | |
452 output.shouldHaveExitValue(1); | |
453 } | |
454 | |
455 public static void testPrintOptions() throws Exception { | |
456 OutputAnalyzer output; | |
457 | |
458 // Test without PrintGC and without PrintStringDeduplicationStatistics | |
459 output = DeduplicationTest.run(SmallNumberOfStrings, | |
460 DefaultAgeThreshold, | |
461 YoungGC); | |
462 output.shouldNotContain("GC concurrent-string-deduplication"); | |
463 output.shouldNotContain("Deduplicated:"); | |
464 output.shouldHaveExitValue(0); | |
465 | |
466 // Test with PrintGC but without PrintStringDeduplicationStatistics | |
467 output = DeduplicationTest.run(SmallNumberOfStrings, | |
468 DefaultAgeThreshold, | |
469 YoungGC, | |
470 "-XX:+PrintGC"); | |
471 output.shouldContain("GC concurrent-string-deduplication"); | |
472 output.shouldNotContain("Deduplicated:"); | |
473 output.shouldHaveExitValue(0); | |
474 } | |
475 | |
476 public static void testInterned() throws Exception { | |
477 // Test that interned strings are deduplicated before being interned | |
478 OutputAnalyzer output = InternedTest.run(); | |
479 output.shouldHaveExitValue(0); | |
480 } | |
481 | |
482 public static void testMemoryUsage() throws Exception { | |
483 // Test that memory usage is reduced after deduplication | |
484 OutputAnalyzer output; | |
485 final String usagePattern = "Heap Memory Usage: (\\d+)"; | |
486 | |
487 // Run without deduplication | |
488 output = MemoryUsageTest.run(false); | |
489 output.shouldHaveExitValue(0); | |
490 final long memoryUsageWithoutDedup = Long.parseLong(output.firstMatch(usagePattern, 1)); | |
491 | |
492 // Run with deduplication | |
493 output = MemoryUsageTest.run(true); | |
494 output.shouldHaveExitValue(0); | |
495 final long memoryUsageWithDedup = Long.parseLong(output.firstMatch(usagePattern, 1)); | |
496 | |
497 // Calculate expected memory usage with deduplication enabled. This calculation does | |
498 // not take alignment and padding into account, so it's a conservative estimate. | |
499 final long sizeOfChar = 2; // bytes | |
500 final long bytesSaved = (LargeNumberOfStrings - 1) * (StringLength * sizeOfChar + unsafe.ARRAY_CHAR_BASE_OFFSET); | |
501 final long memoryUsageWithDedupExpected = memoryUsageWithoutDedup - bytesSaved; | |
502 | |
503 System.out.println("Memory usage summary:"); | |
504 System.out.println(" memoryUsageWithoutDedup: " + memoryUsageWithoutDedup); | |
505 System.out.println(" memoryUsageWithDedup: " + memoryUsageWithDedup); | |
506 System.out.println(" memoryUsageWithDedupExpected: " + memoryUsageWithDedupExpected); | |
507 | |
508 if (memoryUsageWithDedup > memoryUsageWithDedupExpected) { | |
509 throw new Exception("Unexpected memory usage, memoryUsageWithDedup should less or equal to memoryUsageWithDedupExpected"); | |
510 } | |
511 } | |
512 } |