MyBenchmark.java

package org.sample;

import java.util.Arrays;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;

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.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(1)
@State(Scope.Benchmark)
public class MyBenchmark {

    @Param({"100", "1000", "10000", "10000000"})
    public int size;


    @Benchmark
    public double[] randomParallel() {
        double[] vector = new double[size];
        Arrays.parallelSetAll(vector, i -> Math.random());
        return vector;
    }

    @Benchmark
    public double[] randomSequential() {
        double[] vector = new double[size];
        Arrays.setAll(vector, i -> Math.random());
        return vector;
    }

    @Benchmark
    public double[] threadLocalRandomParallel() {
        double[] vector = new double[size];
        Arrays.parallelSetAll(vector, i -> ThreadLocalRandom.current().nextDouble());
        return vector;
    }

    @Benchmark
    public double[] threadLocalRandomSequential() {
        double[] vector = new double[size];
        Arrays.setAll(vector, i -> ThreadLocalRandom.current().nextDouble());
        return vector;
    }

    public static void main(String[] args) throws RunnerException {
        Options opt = new OptionsBuilder()
                .include(MyBenchmark.class.getSimpleName())
                .build();

        new Runner(opt).run();
    }


}