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8038461: Test gc/g1/TestStringDeduplicationMemoryUsage.java fails with unexpected memory usage

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Reviewed-by: jmasa, sjohanss
This commit is contained in:
Per Lidén 2014-04-03 10:39:27 +02:00
parent 1ed5b22d6e
commit 15efa470b9
1 changed files with 22 additions and 11 deletions
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33
hotspot/test/gc/g1/TestStringDeduplicationTools.java
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@ -310,7 +310,9 @@ class TestStringDeduplicationTools {
}
System.gc();
System.out.println("Heap Memory Usage: " + ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed());
System.out.println("Array Header Size: " + unsafe.ARRAY_CHAR_BASE_OFFSET);
System.out.println("End: MemoryUsageTest");
}
@ -482,31 +484,40 @@ class TestStringDeduplicationTools {
public static void testMemoryUsage() throws Exception {
// Test that memory usage is reduced after deduplication
OutputAnalyzer output;
final String usagePattern = "Heap Memory Usage: (\\d+)";
final String heapMemoryUsagePattern = "Heap Memory Usage: (\\d+)";
final String arrayHeaderSizePattern = "Array Header Size: (\\d+)";
// Run without deduplication
output = MemoryUsageTest.run(false);
output.shouldHaveExitValue(0);
final long memoryUsageWithoutDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
final long heapMemoryUsageWithoutDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
final long arrayHeaderSizeWithoutDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
// Run with deduplication
output = MemoryUsageTest.run(true);
output.shouldHaveExitValue(0);
final long memoryUsageWithDedup = Long.parseLong(output.firstMatch(usagePattern, 1));
final long heapMemoryUsageWithDedup = Long.parseLong(output.firstMatch(heapMemoryUsagePattern, 1));
final long arrayHeaderSizeWithDedup = Long.parseLong(output.firstMatch(arrayHeaderSizePattern, 1));
// Sanity check to make sure one instance isn't using compressed class pointers and the other not
if (arrayHeaderSizeWithoutDedup != arrayHeaderSizeWithDedup) {
throw new Exception("Unexpected difference between array header sizes");
}
// Calculate expected memory usage with deduplication enabled. This calculation does
// not take alignment and padding into account, so it's a conservative estimate.
final long sizeOfChar = 2; // bytes
final long bytesSaved = (LargeNumberOfStrings - 1) * (StringLength * sizeOfChar + unsafe.ARRAY_CHAR_BASE_OFFSET);
final long memoryUsageWithDedupExpected = memoryUsageWithoutDedup - bytesSaved;
final long sizeOfChar = unsafe.ARRAY_CHAR_INDEX_SCALE;
final long sizeOfCharArray = StringLength * sizeOfChar + arrayHeaderSizeWithoutDedup;
final long bytesSaved = (LargeNumberOfStrings - 1) * sizeOfCharArray;
final long heapMemoryUsageWithDedupExpected = heapMemoryUsageWithoutDedup - bytesSaved;
System.out.println("Memory usage summary:");
System.out.println(" memoryUsageWithoutDedup: " + memoryUsageWithoutDedup);
System.out.println(" memoryUsageWithDedup: " + memoryUsageWithDedup);
System.out.println(" memoryUsageWithDedupExpected: " + memoryUsageWithDedupExpected);
System.out.println(" heapMemoryUsageWithoutDedup: " + heapMemoryUsageWithoutDedup);
System.out.println(" heapMemoryUsageWithDedup: " + heapMemoryUsageWithDedup);
System.out.println(" heapMemoryUsageWithDedupExpected: " + heapMemoryUsageWithDedupExpected);
if (memoryUsageWithDedup > memoryUsageWithDedupExpected) {
throw new Exception("Unexpected memory usage, memoryUsageWithDedup should less or equal to memoryUsageWithDedupExpected");
if (heapMemoryUsageWithDedup > heapMemoryUsageWithDedupExpected) {
throw new Exception("Unexpected memory usage, heapMemoryUsageWithDedup should be less or equal to heapMemoryUsageWithDedupExpected");
}
}
}