Oracle官方推荐的性能测试工具！简单、精准又直观！-白红宇

Oracle官方推荐的性能测试工具！简单、精准又直观！

阅读量：797 次

发布时间：2023-02-25

本文共 3175 字，大约阅读时间需要 10 分钟。

JMH ?????? Java ??????????? Java ???????? Oracle ?????? JIT???????? JVM?Java ???????????????????????

?????????? JMH ?? StringBuilder.append() ???????????????????

1. ????

????????? JMH ???????? Maven ????????????? JMH ????????????????


       
    
     org.openjdk.jmh
        
    
     jmh-core
        
    
     1.23
    
   
       
    
     org.openjdk.jmh
        
    
     jmh-generator-annprocess
        
    
     1.23

2. ?????

???????????? Java ? StringConnectTest?????????????????????????

public class StringConnectTest {    @Param(value = {"10", "50", "100"})    private int length;    @Benchmark    public void testStringBuilderAdd(Blackhole blackhole) {        StringBuilder sb = new StringBuilder();        for (int i = 0; i < length; i++) {            sb.append(i);        }        blackhole.consume(sb.toString());    }    @Benchmark    public void testStringAdd(Blackhole blackhole) {        String a = "";        for (int i = 0; i < length; i++) {            a += i;        }        blackhole.consume(a);    }    public static void main(String[] args) throws RunnerException {        Options opt = new OptionsBuilder()                .include(StringConnectTest.class.getSimpleName())                .result("result.json")                .resultFormat(ResultFormatType.JSON)                .build();        new Runner(opt).run();    }}

3. ??????

? main ???????? OptionsBuilder ?????????????????????

public static void main(String[] args) throws RunnerException {    Options opt = new OptionsBuilder()            .include(StringConnectTest.class.getSimpleName())            .result("result.json")            .resultFormat(ResultFormatType.JSON)            .build();    new Runner(opt).run();}

4. ??????

?? Maven ???????????????????????

mvn clean install -Djmh_demo=true StringConnectTest

5. ??????

????????????? JSON ??????? result.json??????????????????????????????????????

6. ??????

??????????????? StringBuilder.append() ???? String ????????????????????

????	??	??	??	???? (ns/op)	???
testStringBuilderAdd	100	avgt	5	819.329	0.00%
testStringAdd	100	avgt	5	6490.062	0.00%

???????????????? StringBuilder.append() ????????

7. ?? JMH ???

JMH ??????????????????????????????????????????????

@Benchmark ??????????????

@Param ????????????

@State ????????????

@Warmup ? @Measurement ??????????????????

@Fork ???????????????

8. JMH ????

????????? JMH ????????? Maven ??????????????? Maven ???????


       
            
     
      org.apache.maven.plugins
             
     
      maven-shade-plugin
             
     
      2.4.1
             
                 
                      
       
        package
                       
                           
        
         shade
                        
                       
                           
        
         jmh-demo
                            
         
          
          
           org.openjdk.jmh.Main