JMH 使用指南

package com.gemantic.wealth.yunmatong.service.jmh;

import lombok.extern.slf4j.Slf4j;
import org.openjdk.jmh.annotations.*;
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;
import org.openjdk.jmh.runner.options.TimeValue;

import java.util.concurrent.TimeUnit;

@Slf4j
@BenchmarkMode(Mode.AverageTime)// 测试方法平均执行时间
@OutputTimeUnit(TimeUnit.MICROSECONDS)// 输出结果的时间粒度为微秒
@State(Scope.Benchmark) // 每个测试线程一个实例
public class JMHFirstBenchmark {
    /*
     * Most of the time, you need to maintain some state while the benchmark is
     * running. Since JMH is heavily used to build concurrent benchmarks, we
     * opted for an explicit notion of state-bearing objects.
     *
     * Below are two state objects. Their class names are not essential, it
     * matters they are marked with @State. These objects will be instantiated
     * on demand, and reused during the entire benchmark trial.
     *
     * The important property is that state is always instantiated by one of
     * those benchmark threads which will then have the access to that state.
     * That means you can initialize the fields as if you do that in worker
     * threads (ThreadLocals are yours, etc).
     */

    @State(Scope.Benchmark)
    public static class BenchmarkState {
        volatile double x = Math.PI;
    }

    @State(Scope.Thread)
    public static class ThreadState {
        volatile double x = Math.PI;
    }

    @Benchmark
    public void measureUnshared(ThreadState state) {
        // All benchmark threads will call in this method.
        //
        // However, since ThreadState is the Scope.Thread, each thread
        // will have it's own copy of the state, and this benchmark
        // will measure unshared case.
        state.x++;
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info("measureUnshared:"+ state.x);
    }

    @Benchmark
    public void measureShared(BenchmarkState state) {
        // All benchmark threads will call in this method.
        //
        // Since BenchmarkState is the Scope.Benchmark, all threads
        // will share the state instance, and we will end up measuring
        // shared case.
        state.x++;
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info("measureShared:"+ state.x);
    }

    /*
     * ============================== HOW TO RUN THIS TEST: ====================================
     *
     * You are expected to see the drastic difference in shared and unshared cases,
     * because you either contend for single memory location, or not. This effect
     * is more articulated on large machines.
     *
     * You can run this test:
     *
     * a) Via the command line:
     *    $ mvn clean install
     *    $ java -jar target/benchmarks.jar JMHSample_03 -wi 5 -i 5 -t 4 -f 1
     *    (we requested 5 measurement/warmup iterations, with 4 threads, single fork)
     *
     * b) Via the Java API:
     *    (see the JMH homepage for possible caveats when running from IDE:
     *      http://openjdk.java.net/projects/code-tools/jmh/)
     */

    public static void main(String[] args) throws RunnerException {
        // 可以通过注解
        Options opt = new OptionsBuilder()
                .include(JMHFirstBenchmark.class.getSimpleName())
                .warmupIterations(3) // 预热3次
                .measurementIterations(2).measurementTime(TimeValue.valueOf("1s")) // 运行5次，每次10秒
                .threads(10) // 10线程并发
                .forks(2)
                .build();

        new Runner(opt).run();
    }

}

package com.gemantic.wealth.yunmatong.service.jmh;

import com.gemantic.wealth.yunmatong.service.jmh.service.Calculator;
import com.gemantic.wealth.yunmatong.service.jmh.service.MultithreadCalculator;
import com.gemantic.wealth.yunmatong.service.jmh.service.SinglethreadCalculator;
import org.openjdk.jmh.annotations.*;
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;

import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.All)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@State(Scope.Benchmark)
public class SecondBenchmark {
    @Param({"100000"})
    private int length;
 
    private int[] numbers;
    private Calculator singleThreadCalc;
    private Calculator multiThreadCalc;
 
    public static void main(String[] args) throws RunnerException {
        Options opt = new OptionsBuilder()
                .include(SecondBenchmark.class.getSimpleName()) // .include("JMHF.*") 可支持正则
                .forks(0)
                .warmupIterations(2)
                .measurementIterations(2).threads(10)
                .build();
 
        new Runner(opt).run();
    }

    @Benchmark
    public long singleThreadBench() {
        return singleThreadCalc.sum(numbers);
    }
 
    @Benchmark
    public long multiThreadBench() {
        return multiThreadCalc.sum(numbers);
    }
 
    @Setup(Level.Trial)
    public void prepare() {
        int n = length;
        numbers =new int[n];
        for (int i=0;i<n;i++){
            numbers[i]=i;
        }
        singleThreadCalc = new SinglethreadCalculator();
        multiThreadCalc = new MultithreadCalculator(Runtime.getRuntime().availableProcessors());
    }


    @TearDown
    public void shutdown() {
        singleThreadCalc.shutdown();
        multiThreadCalc.shutdown();
    }
}

package com.gemantic.wealth.yunmatong.service.jmh;

import com.gemantic.wealth.yunmatong.service.jmh.service.Calculator;
import com.gemantic.wealth.yunmatong.service.jmh.service.MultithreadCalculator;
import com.gemantic.wealth.yunmatong.service.jmh.service.SinglethreadCalculator;
import org.openjdk.jmh.annotations.*;
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;
import org.openjdk.jmh.runner.options.TimeValue;

import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@State(Scope.Benchmark)
public class ThirdBenchmark {

    @State(Scope.Group)
    public static class BenchmarkState {
        volatile double x = Math.PI;
    }

    @Benchmark
    @Group("custom")
    @GroupThreads(10)
    public void read(BenchmarkState state) {
        state.x++;
        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("ThirdBenchmark.read: "+ state.x);
    }

    @Benchmark
    @Group("custom")
    public void book(BenchmarkState state) {
        state.x++;
        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("ThirdBenchmark.book: "+ state.x);
    }


    public static void main(String[] args) throws RunnerException {
        Options opt = new OptionsBuilder()
                .include(ThirdBenchmark.class.getSimpleName()) // .include("JMHF.*") 可支持正则
                .forks(0)
                .warmupIterations(0)
                .measurementIterations(2).measurementTime(TimeValue.valueOf("10ms")).threads(5)
                .build();

        new Runner(opt).run();
    }
}