content: /*
   * 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.activemq.artemis.tests.performance.jmh;
  
  import java.util.Arrays;
  import java.util.SplittableRandom;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.activemq.artemis.utils.ByteUtil;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  import org.openjdk.jmh.annotations.Fork;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Mode;
  import org.openjdk.jmh.annotations.OutputTimeUnit;
  import org.openjdk.jmh.annotations.Param;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.Setup;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.Warmup;
  
  @State(Scope.Benchmark)
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  @Fork(2)
  @Warmup(iterations = 5, time = 200, timeUnit = TimeUnit.MILLISECONDS)
  @Measurement(iterations = 8, time = 200, timeUnit = TimeUnit.MILLISECONDS)
  public class ByteArrayHashCodeBenchamark {
  
     @Param({"7", "8", "36"})
     private int length;
  
     @Param("0")
     private int seed;
  
     /**
      * The higher the less predictable for the CPU branch predictor.
      */
     @Param({"4", "10"})
     private int logPermutations;
  
     @Param({"true"})
     private boolean unsafe;
  
     private long seq;
     private int inputMask;
     private byte[][] inputs;
  
     @Setup
     public void init() {
        System.setProperty("io.netty.noUnsafe", Boolean.valueOf(!unsafe).toString());
        int inputSize = 1 << logPermutations;
        inputs = new byte[inputSize][];
        inputMask = inputs.length - 1;
        // splittable random can create repeatable sequence of inputs
        SplittableRandom random = new SplittableRandom(seed);
        for (int i = 0; i < inputs.length; i++) {
           final byte[] bytes = new byte[length];
           for (int b = 0; b < length; b++) {
              bytes[b] = (byte) random.nextInt(Byte.MIN_VALUE, Byte.MAX_VALUE + 1);
           }
           inputs[i] = bytes;
        }
     }
  
     private byte[] nextInput() {
        final long seq = this.seq;
        final int index = (int) (seq & inputMask);
        this.seq = seq + 1;
        return inputs[index];
     }
  
     @Benchmark
     public int artemisHashCode() {
        return ByteUtil.hashCode(nextInput());
     }
  
     @Benchmark
     public int arraysHashCode() {
        return Arrays.hashCode(nextInput());
     }
  
  }
  