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Limit the number of bytes to copy per Unsafe.copyMemory()

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Motivation:

During a large memory copy, safepoint polling is diabled, hindering
accurate profiling.

Modifications:

Only copy up to 1 MiB per Unsafe.copyMemory()

Result:

Potentially more reliable performance
This commit is contained in:
Trustin Lee 2014-05-20 17:16:15 +09:00
parent 108dc23cab
commit 5c6c8da0c9
1 changed files with 25 additions and 6 deletions
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31
common/src/main/java/io/netty/util/internal/PlatformDependent0.java
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@ -42,6 +42,13 @@ final class PlatformDependent0 {
private static final boolean BIG_ENDIAN = ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN;
private static final long ADDRESS_FIELD_OFFSET;
/**
* Limits the number of bytes to copy per {@link Unsafe#copyMemory(long, long, long)} to allow safepoint polling
* during a large copy.
*/
private static final long UNSAFE_COPY_THRESHOLD = 1024L * 1024L;
/**
* {@code true} if and only if the platform supports unaligned access.
*
@ -155,11 +162,9 @@ final class PlatformDependent0 {
}
try {
Cleaner cleaner = ((DirectBuffer) buffer).cleaner();
if (cleaner == null) {
throw new IllegalArgumentException(
"attempted to deallocate the buffer which was allocated via JNIEnv->NewDirectByteBuffer()");
}
if (cleaner != null) {
cleaner.clean();
}
} catch (Throwable t) {
// Nothing we can do here.
}
@ -308,11 +313,25 @@ final class PlatformDependent0 {
}
static void copyMemory(long srcAddr, long dstAddr, long length) {
UNSAFE.copyMemory(srcAddr, dstAddr, length);
//UNSAFE.copyMemory(srcAddr, dstAddr, length);
while (length > 0) {
long size = Math.min(length, UNSAFE_COPY_THRESHOLD);
UNSAFE.copyMemory(srcAddr, dstAddr, size);
length -= size;
srcAddr += size;
dstAddr += size;
}
}
static void copyMemory(Object src, long srcOffset, Object dst, long dstOffset, long length) {
UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, length);
//UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, length);
while (length > 0) {
long size = Math.min(length, UNSAFE_COPY_THRESHOLD);
UNSAFE.copyMemory(src, srcOffset, dst, dstOffset, size);
length -= size;
srcOffset += size;
dstOffset += size;
}
}
static <U, W> AtomicReferenceFieldUpdater<U, W> newAtomicReferenceFieldUpdater(