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comparison test/gc/g1/TestStringDeduplicationTools.java @ 17840:fd8ddf2d2f6b

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8038461: Test gc/g1/TestStringDeduplicationMemoryUsage.java fails with unexpected memory usage Reviewed-by: jmasa, sjohanss
author pliden
date Thu, 03 Apr 2014 10:39:27 +0200
parents 595c0f60d50d
children 660b3f6bf7d7
comparison
equal deleted inserted replaced
17839:5cf196cc5405 17840:fd8ddf2d2f6b
308 if (useStringDeduplication) { 308 if (useStringDeduplication) {
309 verifyStrings(list, numberOfUniqueStrings); 309 verifyStrings(list, numberOfUniqueStrings);
310 } 310 }
311 311
312 System.gc(); 312 System.gc();
313
313 System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed()); 314 System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed());
315 System.out.println("Array Header Size: " + unsafe.ARRAY_CHAR_BASE_OFFSET);
314 316
315 System.out.println("End: MemoryUsageTest"); 317 System.out.println("End: MemoryUsageTest");
316 } 318 }
317 319
318 public static OutputAnalyzer run(boolean useStringDeduplication) throws Exception { 320 public static OutputAnalyzer run(boolean useStringDeduplication) throws Exception {
480 } 482 }
481 483
482 public static void testMemoryUsage() throws Exception { 484 public static void testMemoryUsage() throws Exception {
483 // Test that memory usage is reduced after deduplication 485 // Test that memory usage is reduced after deduplication
484 OutputAnalyzer output; 486 OutputAnalyzer output;
485 final String usagePattern = "Heap Memory Usage: (\\d+)"; 487 final String heapMemoryUsagePattern = "Heap Memory Usage: (\\d+)";
488 final String arrayHeaderSizePattern = "Array Header Size: (\\d+)";
486 489
487 // Run without deduplication 490 // Run without deduplication
488 output = MemoryUsageTest.run(false); 491 output = MemoryUsageTest.run(false);
489 output.shouldHaveExitValue(0); 492 output.shouldHaveExitValue(0);
490 final long memoryUsageWithoutDedup = Long.parseLong(output.firstMatch(usagePattern, 1)); 493 final long heapMemoryUsageWithoutDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
494 final long arrayHeaderSizeWithoutDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
491 495
492 // Run with deduplication 496 // Run with deduplication
493 output = MemoryUsageTest.run(true); 497 output = MemoryUsageTest.run(true);
494 output.shouldHaveExitValue(0); 498 output.shouldHaveExitValue(0);
495 final long memoryUsageWithDedup = Long.parseLong(output.firstMatch(usagePattern, 1)); 499 final long heapMemoryUsageWithDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
500 final long arrayHeaderSizeWithDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
501
502 // Sanity check to make sure one instance isn't using compressed class pointers and the other not
503 if (arrayHeaderSizeWithoutDedup != arrayHeaderSizeWithDedup) {
504 throw new Exception("Unexpected difference between array header sizes");
505 }
496 506
497 // Calculate expected memory usage with deduplication enabled. This calculation does 507 // Calculate expected memory usage with deduplication enabled. This calculation does
498 // not take alignment and padding into account, so it's a conservative estimate. 508 // not take alignment and padding into account, so it's a conservative estimate.
499 final long sizeOfChar = 2; // bytes 509 final long sizeOfChar = unsafe.ARRAY_CHAR_INDEX_SCALE;
500 final long bytesSaved = (LargeNumberOfStrings - 1) * (StringLength * sizeOfChar + unsafe.ARRAY_CHAR_BASE_OFFSET); 510 final long sizeOfCharArray = StringLength * sizeOfChar + arrayHeaderSizeWithoutDedup;
501 final long memoryUsageWithDedupExpected = memoryUsageWithoutDedup - bytesSaved; 511 final long bytesSaved = (LargeNumberOfStrings - 1) * sizeOfCharArray;
512 final long heapMemoryUsageWithDedupExpected = heapMemoryUsageWithoutDedup - bytesSaved;
502 513
503 System.out.println("Memory usage summary:"); 514 System.out.println("Memory usage summary:");
504 System.out.println(" memoryUsageWithoutDedup: " + memoryUsageWithoutDedup); 515 System.out.println(" heapMemoryUsageWithoutDedup: " + heapMemoryUsageWithoutDedup);
505 System.out.println(" memoryUsageWithDedup: " + memoryUsageWithDedup); 516 System.out.println(" heapMemoryUsageWithDedup: " + heapMemoryUsageWithDedup);
506 System.out.println(" memoryUsageWithDedupExpected: " + memoryUsageWithDedupExpected); 517 System.out.println(" heapMemoryUsageWithDedupExpected: " + heapMemoryUsageWithDedupExpected);
507 518
508 if (memoryUsageWithDedup > memoryUsageWithDedupExpected) { 519 if (heapMemoryUsageWithDedup > heapMemoryUsageWithDedupExpected) {
509 throw new Exception("Unexpected memory usage, memoryUsageWithDedup should less or equal to memoryUsageWithDedupExpected"); 520 throw new Exception("Unexpected memory usage, heapMemoryUsageWithDedup should be less or equal to heapMemoryUsageWithDedupExpected");
510 } 521 }
511 } 522 }
512 } 523 }