Combination and log sample of different GC garbage collector

The different JVM parameters used in the old age, the younger generation combination of the following figure.

Give a few examples. 1-XX:+USESERIALGC

Enable serial GC with serial+serial old mode, client mode defaults

2-XX:+USEPARNEWGC

Using the parnew+serial old collector combination is not recommended

2018-04-27t13:19:26.996+0800:3.282: [GC 3.282: [parnew:3276k->743k (92160K), 0.0054274 secs]3.287: [tenured: 361200k->709k (409600K), 0.0113318 secs] 364476k->709k (501760K), [perm:3102k->3102k (21248K)], 0.0168826 secs ] [times:user=0.08 sys=0.00, real=0.02 secs] 

3-XX:+USECONCMARKSWEEPGC

The

uses the parnew+cms+serial old combination for concurrent collection, giving priority to PARNEW+CMS and using an alternative serial old collection when the user thread is low on memory.

2018-04-27t13:23:35.961+0800:1.102: [GC 1.102: [parnew:2780k->744k (78144K), 0.0033055 secs]1.106: [cms:120400k- >713k (173632K), 0.0143163 secs] 123180k->713k (251776K), [CMS perm:3103k->3101k (21248K)], 0.0177658 secs] [ times:user=0.01 sys=0.00, real=0.02 secs] 2018-04-27t13:23:35.994+0800:1.135: [GC [1 cms-initial-mark:121113k (173632K )] 121113K (251840K), 0.0001263 secs] [times:user=0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:35.994+0800:1.135: [CM S-concurrent-mark-start] 2018-04-27t13:23:35.998+0800:1.139: [cms-concurrent-mark:0.003/0.004 secs] [times:user= 0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:35.998+0800:1.139: [Cms-concurrent-preclean-start] 2018-04-27T13 : 23:35.999+0800:1.140: [cms-concurrent-preclean:0.001/0.001 secs] [times:user=0.00 sys=0.00, real=0.00 secs] 2018-04- 27t13:23:35.999+0800:1.140: [Cms-concurrent-abortable-preclean-start] 2018-04-27t13:23:36.995+0800:2.136: [GC 2.136: [parnew:2783k->190k (78208K), 0.0017561 secs]2.137: [cms2018-04-27t13:23:36.996+0800:2.137: [cms-concurrent-abortable-preclean:0.009/0.997 secs] [times:user=0.02 sys= 0.00, real=1.00 secs] (Concurrent mode failure): 121113k->628k (173632K), 0.0136789 secs] 123896k->628k (251840K), [ CMS perm:3104k->3104k (21248K)], 0.0155741 secs] [times:user=0.02 sys=0.00, real=0.02 secs] dddd 2018-04-27t13:23:38 .035+0800:3.176: [GC 3.176: [parnew:0k->0k (78208K), 0.0015648 secs]3.178: [cms:121028k->628k (173632K), 0.0126110 secs] 121028k->628k (251840K), [CMS perm:3104k->3104k (21248K)], 0.0143089 secs] [times:user=0.01 sys=0. real=0.01 secs] 2018-04-27t13:23:38.072+0800:3.213: [GC [1 cms-initial-mark:121028k (173632K)] 121028K (251840K), 0. 0001420 secs] [times:user=0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:38.072+0800:3.213: [ Cms-concurrent-mark-start] 2018-04-27t13:23:38.077+0800:3.218: [cms-concurrent-mark:0.004/0.004 secs] [times:user= 0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:38.077+0800:3.218: [Cms-concurrent-preclean-start] 2018-04-27t13:23:38.078+0800:3.219: [cms-concurrent-preclean:0.001/0.001 secs] [ times:user=0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:38.078+0800:3.219: [Gc[yg occupancy:0 K (78208 k)]3.219: [R  Escan (parallel), 0.0009488 secs]3.220: [Weak refs processing, 0.0000088 secs]3.220: [Scrub string table, 0.0000773 secs] [1 cms-remark:121028k (173632K)] 121028K (251840K), 0.0011589 secs] [times:user=0.00 sys=0.00, real=0.00 secs] 2018-04-2 7T13:23:38.079+0800:3.220: [Cms-concurrent-sweep-start] 2018-04-27t13:23:38.080+0800:3.221: [CMS-concurrent-sweep : 0.000/0.000 secs] [times:user=0.00 sys=0.00, real=0.00 secs] 2018-04-27t13:23:38.080+0800:3.221: [CMS-concurrent-res Et-start] 2018-04-27t13:23:38.081+0800:3.222: [cms-concurrent-reset:0.001/0.001 secs] [times:user=0.00 sys=0.00,  real=0.00 secs]

4-XX:+USEPARALLELGC

Open this parameter using the parallel scavenge & parallel old collector (server mode defaults).
Below is the JDK5 version

[GC [Psyounggen:883k->498k (3584K)] 241683k->241322k (276672K), 0.0024777 secs]
[GC [Psyounggen:498k->498k (3584K)] 241322k->241338k (276672K), 0.0027416 secs]
[Full GC [psyounggen:498k->0k (3584K)] [psoldgen:240840k->371k (17344K)] 241338k->371k (20928K) [Pspermgen: 3284K->3284K (21248K)], 0.0347810 secs]