code: /*
   * Copyright 2012-2018 Chronicle Map Contributors
   *
   * Licensed 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 net.openhft.chronicle.map;
  
  /**
   * Created by peter.lawrey on 28/02/14.
   */
  public class PageLatencyMain {
      public static final int PAGES = Integer.getInteger("pages", 1024 * 1024);
      public static final int PAGES_SIZE = 512; // longs
      public static volatile long b;
  
      public static void main(String... ignored) {
          long[] bytes = new long[PAGES * PAGES_SIZE];
          long maxTime = 0;
          for (int j = 0; j < 10; j++) {
              for (int i = 0; i < PAGES; i++) {
                  long start0 = System.nanoTime();
                  b = bytes[i * PAGES_SIZE];
                  if (b != 0) throw new AssertionError();
                  long time = System.nanoTime() - start0;
                  if (time > maxTime) maxTime = time;
                  if (time > 1e5)
                      System.out.println("Page access time was " + time / 100000 / 10.0 + " ms");
              }
          }
          System.out.println("Longest page access time was " + maxTime / 10000 / 100.0 + " ms");
      }
  }
  