perf: Make use of System.arraycopy directly. (#1001)

bench-jmh/src/main/scala/org/apache/pekko/util/ArrayCopyOf_Benchmark.scala

@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.pekko.util
+
+import org.openjdk.jmh.annotations._
+
+import java.util.concurrent.TimeUnit
+
+@State(Scope.Benchmark)
+@Measurement(timeUnit = TimeUnit.MILLISECONDS)
+class ArrayCopyOf_Benchmark {
+
+  var bs: Array[Byte] = _
+
+  @Param(Array("100", "1000"))
+  var kb = 0
+
+  /*
+    bench-jmh/jmh:run -f 1 -wi 10 -i 10 .*ArrayCopyOf_Benchmark.*
+   */
+
+  @Setup
+  def setup(): Unit = {
+    bs = Array.fill[Byte](1024 * kb)(1)
+  }
+
+  @Benchmark
+  def systemArrayCopy(): Unit = {
+    val len = bs.length
+    val buffer2 = new Array[Byte](bs.length)
+    System.arraycopy(bs, 0, buffer2, 0, len)
+  }
+
+  @Benchmark
+  def arrayCopyOf(): Unit = {
+    val len = bs.length
+    val buffer2 = new Array[Byte](bs.length)
+    Array.copy(bs, 0, buffer2, 0, len)
+  }
+
+}