The HPROF Profiler

The Heap and CPU Profiling Agent (HPROF)是JAVA2 SDK自带的一个简单的profiler代理，它通过与Java Virtual Machine Profiler Interface (JVMPI) 交互，将profiling信息通过本地文件或socket输出ASCII或二进制格式的流。

HPROF可以监控CPU使用率，堆分配统计。除此之外，还可以报告JVM所有监视器和线程的完整的堆的dump状态。

HPROF的JVM参数的语法如下：

-Xrunhprof[:help]|[:param=value,param2=value2, ...]

示例:

-Xrunhprof:file=log.txt,thread=y,depth=3

The file parameter determines where the stack dump is written.

file参数决定dump的堆栈写入到那个文件。

HPROF的详细参数如下：

 

Hprof usage: -Xrunhprof[:help]|[:=
      
       , ...]Option Name and Value   Description             Default---------------------   -----------             -------heap=dump|sites|all     heap profiling          allcpu=samples|old         CPU usage               offformat=a|b              ascii or binary output  afile=
       
                     write data to file      java.hprof                               (.txt for ascii)net=
        
         :
         
                 send data over a socket write to filedepth=
          
            stack trace depth 4cutoff=
           
             output cutoff point 0.0001lineno=y|n line number in traces? ythread=y|n thread in traces? ndoe=y|n dump on exit? y
           
          
         
        
       
      

 

一个javac的示例

Command used: javac -J-agentlib:hprof=cpu=samples Hello.javaCPU SAMPLES BEGIN (total = 126) Fri Oct 22 12:12:14 2004rank   self  accum   count trace method   1 53.17% 53.17%      67 300027 java.util.zip.ZipFile.getEntry   2 17.46% 70.63%      22 300135 java.util.zip.ZipFile.getNextEntry   3  5.56% 76.19%       7 300111 java.lang.ClassLoader.defineClass2   4  3.97% 80.16%       5 300140 java.io.UnixFileSystem.list   5  2.38% 82.54%       3 300149 java.lang.Shutdown.halt0   6  1.59% 84.13%       2 300136 java.util.zip.ZipEntry.initFields   7  1.59% 85.71%       2 300138 java.lang.String.substring   8  1.59% 87.30%       2 300026 java.util.zip.ZipFile.open   9  0.79% 88.10%       1 300118 com.sun.tools.javac.code.Type$ErrorType.
     
        10  0.79% 88.89%       1 300134 java.util.zip.ZipFile.ensureOpen
     

 

参考