--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/test/micro/org/openjdk/bench/java/lang/ArrayCopy.java Fri Oct 05 15:14:31 2018 +0200
@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2014 Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.bench.java.lang;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OperationsPerInvocation;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Benchmark measuring System.arraycopy in different ways.
+ */
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.NANOSECONDS)
+@State(Scope.Thread)
+public class ArrayCopy {
+
+ private static final byte[] TEST_BYTES = "HTTP/1.0".getBytes();
+ private static final char[] TEST_CHARS = new char[46];
+ private static final Object[] TEST_OBJECTS = new Object[200]; // Uses a minimum of 160 internal positions for internal copying
+
+ // a length which the compiler cannot prove is a constant
+ public static int nonConstCharLength = TEST_CHARS.length;
+ public static int nonConstByteLength = TEST_BYTES.length;
+ public static int nonConstObjectLength = TEST_OBJECTS.length;
+
+ // Use this array to copy objects in.
+ public char[] dummyCharArray = new char[TEST_CHARS.length];
+ public byte[] dummyByteArray = new byte[TEST_BYTES.length];
+ public Object[] dummyObjectArray = new Object[TEST_OBJECTS.length];
+
+ @Setup
+ public void setup() {
+ for (int i = 0; i < TEST_OBJECTS.length; i++) {
+ TEST_OBJECTS[i] = new Object();
+ dummyObjectArray[i] = new Object();
+ }
+ }
+
+ /**
+ * This test case do the same work as testArrayCopy. We should make sure
+ * testArrayCopy is equally fast or better. Compare the two and you measure
+ * the system call versus explicit copy for-loop.
+ */
+ @Benchmark
+ public void copyLoop() {
+ for (int j = 0; j < dummyByteArray.length; j++) {
+ dummyByteArray[j] = TEST_BYTES[j];
+ }
+ }
+
+ /**
+ * Test that we can optimize away the code since it should not have any side
+ * effects
+ */
+ @Benchmark
+ public void copyLoopLocalArray() {
+ byte[] localDummyByteArray = new byte[TEST_BYTES.length];
+ for (int j = 0; j < localDummyByteArray.length; j++) {
+ localDummyByteArray[j] = TEST_BYTES[j];
+ }
+ }
+
+ /**
+ * This test case do the same work as testArrayCopy. We should make sure
+ * testArrayCopy is equally fast or better. Compare the two and you measure
+ * the system call versus explicit copy for-loop.
+ * <p/>
+ * Uses non-provable constant length.
+ */
+ @Benchmark
+ public void copyLoopNonConst() {
+ for (int i = 0; i < nonConstByteLength; i++) {
+ dummyByteArray[i] = TEST_BYTES[i];
+ }
+ }
+
+ /**
+ * This test case do the same work as testCopyLoop. We should make sure
+ * testArrayCopy is equally fast or better. Compare the two and you measure
+ * the system call versus explicit copy for-loop.
+ */
+ @Benchmark
+ public void arrayCopy() {
+ System.arraycopy(TEST_BYTES, 0, dummyByteArray, 0, dummyByteArray.length);
+ }
+
+ /**
+ * Test that we can optimize away the code since it should not have any side
+ * effects
+ */
+ @Benchmark
+ public void arrayCopyLocalArray() {
+ byte[] localDummyByteArray = new byte[TEST_BYTES.length];
+ System.arraycopy(TEST_BYTES, 0, localDummyByteArray, 0, localDummyByteArray.length);
+ }
+
+ /**
+ * This test case do the same work as testCopyLoop. We should make sure
+ * testArrayCopy is equally fast or better. Compare the two and you measure
+ * the system call versus explicit copy for-loop.
+ * <p/>
+ * Uses non-provable constant length.
+ */
+ @Benchmark
+ public void arrayCopyNonConst() {
+ System.arraycopy(TEST_BYTES, 0, dummyByteArray, 0, nonConstByteLength);
+ }
+
+ @Benchmark
+ public void arrayCopyChar() {
+ System.arraycopy(TEST_CHARS, 0, dummyCharArray, 0, dummyCharArray.length);
+ }
+
+ @Benchmark
+ public void arrayCopyCharNonConst() {
+ System.arraycopy(TEST_CHARS, 0, dummyCharArray, 0, nonConstCharLength);
+ }
+
+ @Benchmark
+ public void arrayCopyObject() {
+ System.arraycopy(TEST_OBJECTS, 0, dummyObjectArray, 0, dummyObjectArray.length);
+ }
+
+ @Benchmark
+ public void arrayCopyObjectNonConst() {
+ System.arraycopy(TEST_OBJECTS, 0, dummyObjectArray, 0, nonConstObjectLength);
+ }
+
+ /**
+ * This test copies inside a object array, that is same source array as dest
+ * array. Copies backwards in the array.
+ */
+ @Benchmark
+ @OperationsPerInvocation(40)
+ public void arrayCopyObjectSameArraysBackward() {
+ for (int i = 0; i < 40; i++) {
+ System.arraycopy(dummyObjectArray, i, dummyObjectArray, i + 40, 80);
+ }
+ }
+
+ /**
+ * This test copies inside a object array, that is same source array as dest
+ * array. Copies forward in the array. There is a special version for this
+ * in JRockit.
+ */
+ @Benchmark
+ @OperationsPerInvocation(40)
+ public void arrayCopyObjectSameArraysForward() {
+ for (int i = 0; i < 40; i++) {
+ System.arraycopy(dummyObjectArray, i + 40, dummyObjectArray, i, 80);
+ }
+ }
+}