查看JVM各个代的内存状态

╰半夏微凉° 2022-09-18 10:44 171阅读 0赞

//在Linux执行 jmap -heap [pid] 
     
      
     
      
       
      //可以看到如下信息
     
      
     
      
    
     
      
     
      
       
      Attaching to process ID 23990, please wait...
     
      
     
      
       
      Warning: the type "const char*" (declared in the remote VM in VMStructs::localHotSpotVMTypes) had its size declared as 8 twice. Continuing.
     
      
     
      
       
      Warning: the type "const size_t" (declared in the remote VM in VMStructs::localHotSpotVMTypes) had its size declared as 8 twice. Continuing.
     
      
     
      
       
      Warning: the type "const int" (declared in the remote VM in VMStructs::localHotSpotVMTypes) had its size declared as 4 twice. Continuing.
     
      
     
      
       
      Warning: the type "const MemRegion" (declared in the remote VM in VMStructs::localHotSpotVMTypes) had its size declared as 16 twice. Continuing.
     
      
     
      
       
      Debugger attached successfully.
     
      
     
      
       
      Server compiler detected.
     
      
     
      
       
      JVM version is 21.0-b17
     
      
     
      
    
     
      
     
      
       
      using parallel threads in the new generation.
     
      
     
      
       
      using thread-local object allocation.
     
      
     
      
       
      Concurrent Mark-Sweep GC
     
      
     
      
    
     
      
     
      
       
      Heap Configuration:
     
      
     
      
       
         MinHeapFreeRatio = 40
     
      
     
      
       
         MaxHeapFreeRatio = 70
     
      
     
      
       
         MaxHeapSize      = 5368709120 (5120.0MB)
     
      
     
      
       
         NewSize          = 1073741824 (1024.0MB)
     
      
     
      
       
         MaxNewSize       = 1073741824 (1024.0MB)
     
      
     
      
       
         OldSize          = 5439488 (5.1875MB)
     
      
     
      
       
         NewRatio         = 2
     
      
     
      
       
         SurvivorRatio    = 8
     
      
     
      
       
         PermSize         = 536870912 (512.0MB)
     
      
     
      
       
         MaxPermSize      = 536870912 (512.0MB)
     
      
     
      
    
     
      
     
      
       
      Heap Usage:
     
      
     
      
       
      New Generation (Eden + 1 Survivor Space):
     
      
     
      
       
         capacity = 966393856 (921.625MB)
     
      
     
      
       
         used     = 282829160 (269.7269058227539MB)
     
      
     
      
       
         free     = 683564696 (651.8980941772461MB)
     
      
     
      
       
         29.266448482056575% used
     
      
     
      
       
      Eden Space:
     
      
     
      
       
         capacity = 859045888 (819.25MB)
     
      
     
      
       
         used     = 203344848 (193.9247589111328MB)
     
      
     
      
       
         free     = 655701040 (625.3252410888672MB)
     
      
     
      
       
         23.671011157904523% used
     
      
     
      
       
      From Space:
     
      
     
      
       
         capacity = 107347968 (102.375MB)
     
      
     
      
       
         used     = 79484312 (75.8021469116211MB)
     
      
     
      
       
         free     = 27863656 (26.572853088378906MB)
     
      
     
      
       
         74.04361114688263% used
     
      
     
      
       
      To Space:
     
      
     
      
       
         capacity = 107347968 (102.375MB)
     
      
     
      
       
         used     = 0 (0.0MB)
     
      
     
      
       
         free     = 107347968 (102.375MB)
     
      
     
      
       
         0.0% used
     
      
     
      
       
      concurrent mark-sweep generation:
     
      
     
      
       
         capacity = 4294967296 (4096.0MB)
     
      
     
      
       
         used     = 46904664 (44.731773376464844MB)
     
      
     
      
       
         free     = 4248062632 (4051.268226623535MB)
     
      
     
      
       
         1.0920843109488487% used
     
      
     
      
       
      Perm Generation:
     
      
     
      
       
         capacity = 536870912 (512.0MB)
     
      
     
      
       
         used     = 81989448 (78.19123077392578MB)
     
      
     
      
       
         free     = 454881464 (433.8087692260742MB)
     
      
     
      
       
         15.27172476053238% used
     
      
     
      
       
       
     
      
     
      
       
      导出整个JVM的内存
     
      
     
      
       
      jmap -dump:format=b,file=memory.log [pid]
     
      
     
      
       
       
     
      
     
      
       
      使用JHat分析JVM堆dump文件的工具，基于此工具可以分析JVM heap中对象占用状况
     
      
     
      
       
      jhat -J-Xmx1024M [file] 
     
      
     
      
       
      执行后等待console中输出Started HTTP server on port 7000
     
      
     
      
       
      然后就可以使用浏览器访问HTTP：//ip:7000