小编ast*_*llz的帖子

在尝试JDK 8 Streaming功能时,我决定尝试并行/串行流性能测试.我尝试使用在单位正方形上投掷随机飞镖来解决pi的值,并检查单位圆内有多少次着陆.我找到了apache-spark的例子.

这是代码.

    package org.sample;

    import java.util.concurrent.TimeUnit;
    import java.util.stream.IntStream;

    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;

    @BenchmarkMode(Mode.AverageTime)
    @OutputTimeUnit(TimeUnit.NANOSECONDS)
    @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({
            "1000000",
            "10000000"
        }) int MAX_COUNT;

        @Benchmark
        public double parallelPiTest() {
            long count = IntStream.range(1, MAX_COUNT).parallel().filter(i -> {
                double x= Math.random(); 
                double y= Math.random(); …