jmap

jmap

此命令用来查看内存信息，实例个数以及占用内存大小

 

jmap

jmap -histo -F  27515 >  ./log.txt

 

 

查看堆信息

jmap -heap 进程Id

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Attaching to process ID 27515, please wait... Debugger attached successfully. Server compiler detected. JVM version is 25.201-b09   using parallel threads in the new generation. using thread-local object allocation. Concurrent Mark-Sweep GC   Heap Configuration:    MinHeapFreeRatio         = 40    MaxHeapFreeRatio         = 70    MaxHeapSize              = 536870912 (512.0MB)    NewSize                  = 178913280 (170.625MB)    MaxNewSize               = 178913280 (170.625MB)    OldSize                  = 89522176 (85.375MB)    NewRatio                 = 2    SurvivorRatio            = 2    MetaspaceSize            = 21807104 (20.796875MB)    CompressedClassSpaceSize = 1073741824 (1024.0MB)    MaxMetaspaceSize         = 17592186044415 MB    G1HeapRegionSize         = 0 (0.0MB)   Heap Usage: New Generation (Eden + 1 Survivor Space):    capacity = 134217728 (128.0MB)    used     = 17779880 (16.956214904785156MB)    free     = 116437848 (111.04378509521484MB)    13.247042894363403% used Eden Space:    capacity = 89522176 (85.375MB)    used     = 9343864 (8.911003112792969MB)    free     = 80178312 (76.46399688720703MB)    10.437485344413433% used From Space:    capacity = 44695552 (42.625MB)    used     = 8436016 (8.045211791992188MB)    free     = 36259536 (34.57978820800781MB)    18.874397165964076% used To Space:    capacity = 44695552 (42.625MB)    used     = 0 (0.0MB)    free     = 44695552 (42.625MB)    0.0% used concurrent mark-sweep generation:    capacity = 201170944 (191.8515625MB)    used     = 128766432 (122.80123901367188MB)    free     = 72404512 (69.05032348632812MB)    64.0084643635216% used

　　

堆内存dump

jmap -dump:format=b,file=xxx.hprof  进程Id