Java Benchmark 基准测试的实例详解

Java Benchmark 基准测试的实例详解

import java.util.Arrays; 
import java.util.concurrent.TimeUnit; 
 
import org.openjdk.jmh.annotations.Benchmark; 
import org.openjdk.jmh.annotations.BenchmarkMode; 
import org.openjdk.jmh.annotations.Measurement; 
import org.openjdk.jmh.annotations.Mode; 
import org.openjdk.jmh.annotations.OutputTimeUnit; 
import org.openjdk.jmh.annotations.Scope; 
import org.openjdk.jmh.annotations.State; 
import org.openjdk.jmh.annotations.Threads; 
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.Throughput)//基准测试类型 
@OutputTimeUnit(TimeUnit.SECONDS)//基准测试结果的时间类型 
@Warmup(iterations = 3)//预热的迭代次数 
@Threads(2)//测试线程数量 
@State(Scope.Thread)//该状态为每个线程独享 
//度量:iterations进行测试的轮次，time每轮进行的时长，timeUnit时长单位,batchSize批次数量 
@Measurement(iterations = 2, time = -1, timeUnit = TimeUnit.SECONDS, batchSize = -1) 
public class InstructionsBenchmark{ 
  static int staticPos = 0; 
  //String src = "SELECt a FROM ab, ee.ff AS f,(SELECt a FROM `schema_bb`.`tbl_bb`,(SELECt a FROM ccc AS c, `dddd`));"; 
  final byte[] srcBytes = {83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 97, 98, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 44, 32, 101, 101, 46, 102, 102, 32, 65, 83, 32, 102, 44, 40, 83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 96, 115, 99, 104, 101, 109, 97, 95, 98, 98, 96, 46, 96, 116, 98, 108, 95, 98, 98, 96, 44, 40, 83, 69, 76, 69, 67, 84, 32, 97, 32, 70, 82, 79, 77, 32, 99, 99, 99, 32, 65, 83, 32, 99, 44, 32, 96, 100, 100, 100, 100, 96, 41, 41, 59}; 
  int len = srcBytes.length; 
  byte[] array = new byte[8192]; 
  int memberVariable = 0; 
 
  //run 
  public static void main(String[] args) throws RunnerException { 
    Options opt = new OptionsBuilder() 
 .include(InstructionsBenchmark.class.getSimpleName()) 
 .forks(1) 
 //   使用之前要安装hsdis 
 //-XX:-TieredCompilation 关闭分层优化 -server 
 //-XX:+LogCompilation 运行之后项目路径会出现按照测试顺序输出hotspot_pid.log文件,可以使用JITWatch进行分析,可以根据最后运行的结果的顺序按文件时间找到对应的hotspot_pid.log文件 
 .jvmArgs("-XX:+UnlockDiagnosticVMOptions", "-XX:+LogCompilation", "-XX:+TraceClassLoading", "-XX:+PrintAssembly") 
 // .addProfiler(CompilerProfiler.class)  // report JIT compiler profiling via standard MBeans 
 // .addProfiler(GCProfiler.class)  // report GC time 
 // .addProfiler(StackProfiler.class) // report method stack execution profile 
 // .addProfiler(PausesProfiler.class) 
  
 //.addProfiler(WinPerfAsmProfiler.class) 
 //更多Profiler,请看JMH介绍 
 //.output("InstructionsBenchmark.log")//输出信息到文件 
 .build(); 
    new Runner(opt).run(); 
  } 
 
 
  //空循环 对照项 
  @Benchmark 
  public int emptyLoop() { 
    int pos = 0; 
    while (pos < len) { 
      ++pos; 
    } 
    return pos; 
  } 
 
  @Benchmark 
  public int increment() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      ++result; 
      ++pos; 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int decrement() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      --result; 
      ++pos; 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int ifElse() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      if (pos == 10) { 
 ++result; 
 ++pos; 
      } else { 
 ++pos; 
      } 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int ifElse2() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      if (pos == 10) { 
 ++result; 
 ++pos; 
      } else if (pos == 20) { 
 ++result; 
 ++pos; 
      } else { 
 ++pos; 
      } 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int ifnotElse() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      if (pos != 10) { 
 ++pos; 
      } else { 
 ++result; 
 ++pos; 
      } 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int ifLessthanElse() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      if (pos < 10) { 
 ++pos; 
      } else { 
 ++result; 
 ++pos; 
      } 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int ifGreaterthanElse() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      if (pos > 10) { 
 ++pos; 
      } else { 
 ++result; 
 ++pos; 
      } 
    } 
    return result; 
  } 
 
  @Benchmark 
  public int readMemberVariable_a_byteArray() { 
    int pos = 0; 
    int result = 0; 
    while (pos < len) { 
      result = srcBytes[pos]; 
      pos++; 
    } 
    return result; 
  } 
 
} 

 ops/time：标识每秒钟执行的次数

 依赖jar包：

 
      org.openjdk.jmh 
      jmh-core 
      ${jmh.version} 
     
     
      org.openjdk.jmh 
      jmh-generator-annprocess 
      ${jmh.version} 
      provided 
     

 
     
       
 org.codehaus.mojo 
 exec-maven-plugin 
  
    
     run-benchmarks 
     integration-test 
      
exec 
      
      
test 
java 
 
  -classpath 
   
  org.openjdk.jmh.Main 
  .* 
 
      
    
  
       
     
   

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