| /* |
| * Copyright (C) 2013 The Guava Authors |
| * |
| * 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 com.google.common.collect; |
| |
| import com.google.caliper.BeforeExperiment; |
| import com.google.caliper.Benchmark; |
| import com.google.caliper.Param; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.Random; |
| |
| /** |
| * A benchmark to determine the overhead of sorting with {@link Ordering#from(Comparator)}, or with |
| * {@link Ordering#natural()}, as opposed to using the inlined {@link Arrays#sort(Object[])} |
| * implementation, which uses {@link Comparable#compareTo} directly. |
| * |
| * @author Louis Wasserman |
| */ |
| public class ComparatorDelegationOverheadBenchmark { |
| private final Integer[][] inputArrays = new Integer[0x100][]; |
| |
| @Param({"10000"}) |
| int n; |
| |
| @BeforeExperiment |
| void setUp() throws Exception { |
| Random rng = new Random(); |
| for (int i = 0; i < 0x100; i++) { |
| Integer[] array = new Integer[n]; |
| for (int j = 0; j < n; j++) { |
| array[j] = rng.nextInt(); |
| } |
| inputArrays[i] = array; |
| } |
| } |
| |
| @Benchmark |
| int arraysSortNoComparator(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| Integer[] copy = inputArrays[i & 0xFF].clone(); |
| Arrays.sort(copy); |
| tmp += copy[0]; |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int arraysSortOrderingNatural(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| Integer[] copy = inputArrays[i & 0xFF].clone(); |
| Arrays.sort(copy, Ordering.natural()); |
| tmp += copy[0]; |
| } |
| return tmp; |
| } |
| |
| private static final Comparator<Integer> NATURAL_INTEGER = |
| new Comparator<Integer>() { |
| @Override |
| public int compare(Integer o1, Integer o2) { |
| return o1.compareTo(o2); |
| } |
| }; |
| |
| @Benchmark |
| int arraysSortOrderingFromNatural(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| Integer[] copy = inputArrays[i & 0xFF].clone(); |
| Arrays.sort(copy, Ordering.from(NATURAL_INTEGER)); |
| tmp += copy[0]; |
| } |
| return tmp; |
| } |
| } |