JVM tuning summary, jvm Tuning
Auxiliary Information
JVM provides a large number of command line parameters and prints information for debugging. There are mainly the following:
- -XX: + PrintGC
Output Format: [GC 118250 K-> 113543 K (130112 K), 0.0094143 secs][Full GC 121376 K-> 10414 K (130112 K), 0.0650971 secs]
- -XX: + PrintGCDetails
Output Format: [GC [DefNew: 8614 K-> 781 K (9088 K), 0.0123035 secs] 118250 K-> 113543 K (130112 K), 0.0124633 secs][GC [DefNew: 8614 K-> 8614 K (9088 K), 0.0000665 secs] [Tenured: 112761 K-> 10414 K (121024 K ), 0.0433488 secs] 121376 K-> 10414 K (130112 K), 0.0436268 secs]
- -XX: + PrintGCTimeStamps-XX: + PrintGC: PrintGCTimeStamps can be used together with the above two
Output Format:11.851: [GC 98328 K-> 93620 K (130112 K), 0.0082960 secs]
- -XX: + PrintGCApplicationConcurrentTime:Print the execution time of the program before each garbage collection. Can be used together with the above
Output Format:Application time: 0.5291524 seconds
- -XX: + PrintGCApplicationStoppedTime: Print the time when the program is suspended during garbage collection. Can be used together with the above
Output Format:Total time for which application threads were stopped: 0.0468229 seconds
- -XX: PrintHeapAtGC: Print detailed stack information before and after GC
Output Format:
34.702: [GC {Heap before gc invocations = 7:
Def new generation total 55296 K, used 52568 K [0x1ebd0000, 0x227d0000, 0x227d0000)
Eden space 49152 K, 99% used[0x1ebd0000, 0x21bce430, 0x21bd0000)
From space 6144 K, 55% used[0x221d0000, 0x22527e10, 0x227d0000)
To space 6144 K, 0% used [0x21bd0000, 0x21bd0000, 0x221d0000)
Tenured generation total 69632 K, used 2696 K [0x227d0000, 0x26bd0000, 0x26bd0000)
The space 69632 K, 3% used[0x227d0000, 0x22a720f8, 0x22a72200, 0x26bd0000)
Compacting perm gen total 8192 K, used 2898 K [0x26bd0000, 0x273d0000, 0x2abd0000)
The space 8192 K, 35% used [0x26bd0000, 0x26ea4ba8, 0x26ea4c00, 0x273d0000)
Ro space 8192 K, 66% used [0x2abd0000, 0x2b12bcc0, 0x2b12be00, 0x2b3d0000)
Rw space 12288 K, 46% used [0x2b3d0000, 0x2b972060, 0x2b972200, 0x2bfd0000)
34.735: [DefNew: 52568 K-> 3433 K (55296 K), 0.0072126 secs] 55264 K-> 6615 K (124928 K)Heap after gc invocations = 8:
Def new generation total 55296 K, used 3433 K [0x1ebd0000, 0x227d0000, 0x227d0000)
Eden space 49152 K, 0% used[0x1ebd0000, 0x1ebd0000, 0x21bd0000)
From space 6144 K, 55% used [0x21bd0000, 0x21f2a5e8, 0x221d0000)
To space 6144 K, 0% used [0x221d0000, 0x221d0000, 0x227d0000)
Tenured generation total 69632 K, used 3182 K [0x227d0000, 0x26bd0000, 0x26bd0000)
The space 69632 K, 4% used[0x227d0000, 0x22aeb958, 0x22aeba00, 0x26bd0000)
Compacting perm gen total 8192 K, used 2898 K [0x26bd0000, 0x273d0000, 0x2abd0000)
The space 8192 K, 35% used [0x26bd0000, 0x26ea4ba8, 0x26ea4c00, 0x273d0000)
Ro space 8192 K, 66% used [0x2abd0000, 0x2b12bcc0, 0x2b12be00, 0x2b3d0000)
Rw space 12288 K, 46% used [0x2b3d0000, 0x2b972060, 0x2b972200, 0x2bfd0000)
}
, 0.0757599 secs]
- -Xloggc: filename: Used in combination with the above, the relevant log information is recorded in the file for analysis.
Common configuration Summary
Iv. Optimization Summary
