perf: added simple list benchmark to check jdk compiler optimization

engine/src/test/java/performance/ListBenchmark.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2023 Arcade Data Ltd
+ *
+ * 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 performance;
+
+import java.util.*;
+
+public class ListBenchmark {
+  private final static int REPEAT = 100;
+  private final static int TOTAL  = 1_000_000;
+
+  public static void main(String[] args) {
+    final List<Integer> list = new ArrayList<>(TOTAL);
+
+    for (int i = 0; i < TOTAL; i++)
+      list.add(i);
+
+    // WARM UP
+    Result result = getResult(list);
+    System.out.println("WARMUP: Total array: " + result.totalArray() + " (" + result.totalNumbers() + ")");
+    System.out.println("WARMUP: Total iterator: " + result.totalIterator() + " (" + result.totalNumbers() + ")");
+
+    // BENCHMARK
+    result = getResult(list);
+
+    System.out.println("Total array: " + result.totalArray() + " (" + result.totalNumbers() + ")");
+    System.out.println("Total iterator: " + result.totalIterator() + " (" + result.totalNumbers() + ")");
+  }
+
+  private static Result getResult(final List<Integer> list) {
+    long totalNumbers = 0L; // THIS IS JUST TO AVOID COMPILER OPTIMIZATION AND REMOVAL OF THE ENTIRE LINE
+    long totalArray = 0L;
+    long totalIterator = 0L;
+
+    for (int k = 0; k < 100; k++) {
+      long begin = System.currentTimeMillis();
+
+      for (int j = 0; j < REPEAT; j++)
+        for (Integer i : list)
+          totalNumbers += i; // THIS IS JUST TO AVOID COMPILER OPTIMIZATION AND REMOVAL OF THE ENTIRE LINE
+
+      totalIterator += System.currentTimeMillis() - begin;
+
+      begin = System.currentTimeMillis();
+
+      for (int j = 0; j < REPEAT; j++)
+        for (int i = 0; i < TOTAL; i++)
+          totalNumbers += list.get(i); // THIS IS JUST TO AVOID COMPILER OPTIMIZATION AND REMOVAL OF THE ENTIRE LINE
+
+      totalArray += System.currentTimeMillis() - begin;
+    }
+    Result result = new Result(totalNumbers, totalArray, totalIterator);
+    return result;
+  }
+
+  private record Result(long totalNumbers, long totalArray, long totalIterator) {
+  }
+}