/
LessThanBenchmark.java
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/
LessThanBenchmark.java
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/*
* 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;
}
}