JVM实施监控

这些不怎么常用的功能，用起来真的很强大；

 

jqs  查看当前java进程信息；

 

 

javavisualvm 查询jvm及heap性能

我这下载了jvmstat插件；当然jvmstat也可以单独下载安装；具体使用参考：visualgc

 

 

 

 

 

 

 

jconsole

 

 

 

 

 

 

以下是针对Linux的一些使用：

 

 

 jstat -compiler <pid>  显示VM实时编译的数量

 jmap -heap <pid> 显示heap信息

 

root@iZ25onac7oyZ:~# jmap -heap 6800
Attaching to process ID 6800, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 24.55-b03

using thread-local object allocation.
Mark Sweep Compact GC

Heap Configuration:
   MinHeapFreeRatio = 40
   MaxHeapFreeRatio = 70
   MaxHeapSize      = 262144000 (250.0MB)
   NewSize          = 1310720 (1.25MB)
   MaxNewSize       = 17592186044415 MB
   OldSize          = 5439488 (5.1875MB)
   NewRatio         = 2
   SurvivorRatio    = 8
   PermSize         = 21757952 (20.75MB)
   MaxPermSize      = 85983232 (82.0MB)
   G1HeapRegionSize = 0 (0.0MB)

Heap Usage:
New Generation (Eden + 1 Survivor Space):
   capacity = 15073280 (14.375MB)
   used     = 4903816 (4.676643371582031MB)
   free     = 10169464 (9.698356628417969MB)
   32.53317128057065% used
Eden Space:
   capacity = 13434880 (12.8125MB)
   used     = 4903816 (4.676643371582031MB)
   free     = 8531064 (8.135856628417969MB)
   36.500631192835364% used
From Space:
   capacity = 1638400 (1.5625MB)
   used     = 0 (0.0MB)
   free     = 1638400 (1.5625MB)
   0.0% used
To Space:
   capacity = 1638400 (1.5625MB)
   used     = 0 (0.0MB)
   free     = 1638400 (1.5625MB)
   0.0% used
tenured generation:
   capacity = 33300480 (31.7578125MB)
   used     = 19977912 (19.05242156982422MB)
   free     = 13322568 (12.705390930175781MB)
   59.99286496771218% used
Perm Generation:
   capacity = 21757952 (20.75MB)
   used     = 19360632 (18.46373748779297MB)
   free     = 2397320 (2.2862625122070312MB)
   88.98186741105046% used

11947 interned Strings occupying 1627776 bytes.