jmap使用

原创转载请注明出处：https://agilestyle.iteye.com/blog/2439738

 

使用 -heap 查看heap空间概要

jmap -heap 41565 > ~/jmap.txt

 Console Output

Attaching to process ID 41565, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.131-b11

using parallel threads in the new generation.
using thread-local object allocation.
Concurrent Mark-Sweep GC

Heap Configuration:
   MinHeapFreeRatio         = 40
   MaxHeapFreeRatio         = 70
   MaxHeapSize              = 1073741824 (1024.0MB)
   NewSize                  = 89456640 (85.3125MB)
   MaxNewSize               = 348913664 (332.75MB)
   OldSize                  = 178978816 (170.6875MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 0 (0.0MB)

Heap Usage:
New Generation (Eden + 1 Survivor Space):
   capacity = 314048512 (299.5MB)
   used     = 314048496 (299.49998474121094MB)
   free     = 16 (1.52587890625E-5MB)
   99.99999490524573% used
Eden Space:
   capacity = 279183360 (266.25MB)
   used     = 279183360 (266.25MB)
   free     = 0 (0.0MB)
   100.0% used
From Space:
   capacity = 34865152 (33.25MB)
   used     = 34865136 (33.24998474121094MB)
   free     = 16 (1.52587890625E-5MB)
   99.99995410890507% used
To Space:
   capacity = 34865152 (33.25MB)
   used     = 0 (0.0MB)
   free     = 34865152 (33.25MB)
   0.0% used
concurrent mark-sweep generation:
   capacity = 724828160 (691.25MB)
   used     = 724828160 (691.25MB)
   free     = 0 (0.0MB)
   100.0% used

38460 interned Strings occupying 4469136 bytes.

 

使用 -histo:live 查看内存中有哪些对象

jmap -histo:live 41565 > ~/jmap.txt

 

reference

https://docs.oracle.com/javase/8/docs/technotes/tools/unix/jmap.html

https://www.cnblogs.com/yjd_hycf_space/p/7753847.html