1 /* 2 * Copyright (C) 2013 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 5 * in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the License 10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 11 * or implied. See the License for the specific language governing permissions and limitations under 12 * the License. 13 */ 14 15 package com.google.common.collect; 16 17 import com.google.caliper.BeforeExperiment; 18 import com.google.caliper.Benchmark; 19 import com.google.caliper.Param; 20 21 import java.util.Arrays; 22 import java.util.Comparator; 23 import java.util.Random; 24 25 /** 26 * A benchmark to determine the overhead of sorting with {@link Ordering#from(Comparator)}, or with 27 * {@link Ordering#natural()}, as opposed to using the inlined {@link Arrays#sort(Object[])} 28 * implementation, which uses {@link Comparable#compareTo} directly. 29 * 30 * @author Louis Wasserman 31 */ 32 public class ComparatorDelegationOverheadBenchmark { 33 private final Integer[][] inputArrays = new Integer[0x100][]; 34 35 @Param({"10000"}) 36 int n; 37 38 @BeforeExperiment setUp()39 void setUp() throws Exception { 40 Random rng = new Random(); 41 for (int i = 0; i < 0x100; i++) { 42 Integer[] array = new Integer[n]; 43 for (int j = 0; j < n; j++) { 44 array[j] = rng.nextInt(); 45 } 46 inputArrays[i] = array; 47 } 48 } 49 arraysSortNoComparator(int reps)50 @Benchmark int arraysSortNoComparator(int reps) { 51 int tmp = 0; 52 for (int i = 0; i < reps; i++) { 53 Integer[] copy = inputArrays[i & 0xFF].clone(); 54 Arrays.sort(copy); 55 tmp += copy[0]; 56 } 57 return tmp; 58 } 59 arraysSortOrderingNatural(int reps)60 @Benchmark int arraysSortOrderingNatural(int reps) { 61 int tmp = 0; 62 for (int i = 0; i < reps; i++) { 63 Integer[] copy = inputArrays[i & 0xFF].clone(); 64 Arrays.sort(copy, Ordering.natural()); 65 tmp += copy[0]; 66 } 67 return tmp; 68 } 69 70 private static final Comparator<Integer> NATURAL_INTEGER = new Comparator<Integer>() { 71 @Override 72 public int compare(Integer o1, Integer o2) { 73 return o1.compareTo(o2); 74 } 75 }; 76 arraysSortOrderingFromNatural(int reps)77 @Benchmark int arraysSortOrderingFromNatural(int reps) { 78 int tmp = 0; 79 for (int i = 0; i < reps; i++) { 80 Integer[] copy = inputArrays[i & 0xFF].clone(); 81 Arrays.sort(copy, Ordering.from(NATURAL_INTEGER)); 82 tmp += copy[0]; 83 } 84 return tmp; 85 } 86 } 87