| /* |
| * 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.math; |
| |
| import com.google.caliper.BeforeExperiment; |
| import com.google.caliper.Benchmark; |
| import com.google.caliper.Param; |
| import java.util.Random; |
| |
| /** |
| * Benchmarks for various ways of writing the expression {@code foo + ((bar < baz) ? 1 : 0)}. |
| * |
| * @author Louis Wasserman |
| */ |
| public class LessThanBenchmark { |
| static final int SAMPLE_SIZE = 0x1000; |
| static final int SAMPLE_MASK = 0x0FFF; |
| |
| @Param("1234") |
| int randomSeed; |
| |
| int[] xInts; |
| int[] yInts; |
| |
| long[] xLongs; |
| long[] yLongs; |
| |
| int[] constant; |
| |
| private static final long NONNEGATIVE_LONG_MASK = 0x7FFFFFFFFFFFFFFFL; |
| |
| @BeforeExperiment |
| void setUp() { |
| Random random = new Random(randomSeed); |
| xInts = new int[SAMPLE_SIZE]; |
| yInts = new int[SAMPLE_SIZE]; |
| xLongs = new long[SAMPLE_SIZE]; |
| yLongs = new long[SAMPLE_SIZE]; |
| constant = new int[SAMPLE_SIZE]; |
| for (int i = 0; i < SAMPLE_SIZE; i++) { |
| xInts[i] = random.nextInt(Integer.MAX_VALUE); |
| yInts[i] = random.nextInt(Integer.MAX_VALUE); |
| xLongs[i] = random.nextLong() & NONNEGATIVE_LONG_MASK; |
| yLongs[i] = random.nextLong() & NONNEGATIVE_LONG_MASK; |
| constant[i] = random.nextInt(); |
| } |
| } |
| |
| @Benchmark |
| int branchFreeLtIntInlined(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| int x = xInts[j]; |
| int y = yInts[j]; |
| int z = constant[j]; |
| tmp += z + ((x - y) >>> (Integer.SIZE - 1)); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int branchFreeLtInt(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| int x = xInts[j]; |
| int y = yInts[j]; |
| int z = constant[j]; |
| tmp += z + IntMath.lessThanBranchFree(x, y); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int ternaryLtIntAddOutsideTernary(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| int x = xInts[j]; |
| int y = yInts[j]; |
| int z = constant[j]; |
| tmp += z + ((x < y) ? 1 : 0); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int ternaryLtIntAddInsideTernary(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| int x = xInts[j]; |
| int y = yInts[j]; |
| int z = constant[j]; |
| tmp += (x < y) ? z + 1 : z; |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int branchFreeLtLongInlined(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| long x = xLongs[j]; |
| long y = yLongs[j]; |
| int z = constant[j]; |
| tmp += z + (int) ((x - y) >>> (Long.SIZE - 1)); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int branchFreeLtLong(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| long x = xLongs[j]; |
| long y = yLongs[j]; |
| int z = constant[j]; |
| tmp += z + LongMath.lessThanBranchFree(x, y); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int ternaryLtLongAddOutsideTernary(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| long x = xLongs[j]; |
| long y = yLongs[j]; |
| int z = constant[j]; |
| tmp += z + ((x < y) ? 1 : 0); |
| } |
| return tmp; |
| } |
| |
| @Benchmark |
| int ternaryLtLongAddInsideTernary(int reps) { |
| int tmp = 0; |
| for (int i = 0; i < reps; i++) { |
| int j = i & SAMPLE_MASK; |
| long x = xLongs[j]; |
| long y = yLongs[j]; |
| int z = constant[j]; |
| tmp += (x < y) ? z + 1 : z; |
| } |
| return tmp; |
| } |
| } |