1.1 --- a/test/gc/g1/TestStringDeduplicationTools.java Sat Apr 05 23:38:24 2014 -0700
1.2 +++ b/test/gc/g1/TestStringDeduplicationTools.java Thu Apr 03 10:39:27 2014 +0200
1.3 @@ -310,7 +310,9 @@
1.4 }
1.5
1.6 System.gc();
1.7 +
1.8 System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed());
1.9 + System.out.println("Array Header Size: " + unsafe.ARRAY_CHAR_BASE_OFFSET);
1.10
1.11 System.out.println("End: MemoryUsageTest");
1.12 }
1.13 @@ -482,31 +484,40 @@
1.14 public static void testMemoryUsage() throws Exception {
1.15 // Test that memory usage is reduced after deduplication
1.16 OutputAnalyzer output;
1.17 - final String usagePattern = "Heap Memory Usage: (\\d+)";
1.18 + final String heapMemoryUsagePattern = "Heap Memory Usage: (\\d+)";
1.19 + final String arrayHeaderSizePattern = "Array Header Size: (\\d+)";
1.20
1.21 // Run without deduplication
1.22 output = MemoryUsageTest.run(false);
1.23 output.shouldHaveExitValue(0);
1.24 - final long memoryUsageWithoutDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
1.25 + final long heapMemoryUsageWithoutDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
1.26 + final long arrayHeaderSizeWithoutDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
1.27
1.28 // Run with deduplication
1.29 output = MemoryUsageTest.run(true);
1.30 output.shouldHaveExitValue(0);
1.31 - final long memoryUsageWithDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
1.32 + final long heapMemoryUsageWithDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
1.33 + final long arrayHeaderSizeWithDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
1.34 +
1.35 + // Sanity check to make sure one instance isn't using compressed class pointers and the other not
1.36 + if (arrayHeaderSizeWithoutDedup != arrayHeaderSizeWithDedup) {
1.37 + throw new Exception("Unexpected difference between array header sizes");
1.38 + }
1.39
1.40 // Calculate expected memory usage with deduplication enabled. This calculation does
1.41 // not take alignment and padding into account, so it's a conservative estimate.
1.42 - final long sizeOfChar = 2; // bytes
1.43 - final long bytesSaved = (LargeNumberOfStrings - 1) * (StringLength * sizeOfChar + unsafe.ARRAY_CHAR_BASE_OFFSET);
1.44 - final long memoryUsageWithDedupExpected = memoryUsageWithoutDedup - bytesSaved;
1.45 + final long sizeOfChar = unsafe.ARRAY_CHAR_INDEX_SCALE;
1.46 + final long sizeOfCharArray = StringLength * sizeOfChar + arrayHeaderSizeWithoutDedup;
1.47 + final long bytesSaved = (LargeNumberOfStrings - 1) * sizeOfCharArray;
1.48 + final long heapMemoryUsageWithDedupExpected = heapMemoryUsageWithoutDedup - bytesSaved;
1.49
1.50 System.out.println("Memory usage summary:");
1.51 - System.out.println(" memoryUsageWithoutDedup: " + memoryUsageWithoutDedup);
1.52 - System.out.println(" memoryUsageWithDedup: " + memoryUsageWithDedup);
1.53 - System.out.println(" memoryUsageWithDedupExpected: " + memoryUsageWithDedupExpected);
1.54 + System.out.println(" heapMemoryUsageWithoutDedup: " + heapMemoryUsageWithoutDedup);
1.55 + System.out.println(" heapMemoryUsageWithDedup: " + heapMemoryUsageWithDedup);
1.56 + System.out.println(" heapMemoryUsageWithDedupExpected: " + heapMemoryUsageWithDedupExpected);
1.57
1.58 - if (memoryUsageWithDedup > memoryUsageWithDedupExpected) {
1.59 - throw new Exception("Unexpected memory usage, memoryUsageWithDedup should less or equal to memoryUsageWithDedupExpected");
1.60 + if (heapMemoryUsageWithDedup > heapMemoryUsageWithDedupExpected) {
1.61 + throw new Exception("Unexpected memory usage, heapMemoryUsageWithDedup should be less or equal to heapMemoryUsageWithDedupExpected");
1.62 }
1.63 }
1.64 }
