在全GC事件发生后，G1收集器采用长年轻（轻微gc）暂停时间

Question

One of my application shows weird GC behavior. 我的一个应用程序显示了奇怪的GC行为。 Application does young gc (minor GC) at regular intervals with pause time of ~30-50 ms and occasionally does mixed gc with ~100-150 ms this is never problem in healthy running state until jvm or we initiate Full GC. 应用定期进行年轻gc（次要GC），暂停时间为~30-50 ms，偶尔混合gc约为100-150 ms，这在健康运行状态下永远不会出现问题，直到jvm或我们启动Full GC。

After a Full GC event, we see that consecutive young gen gc (minor gc) pause time keeps increasing, and goes above MaxGCPauseMillis of 200 ms. 在Full GC事件之后，我们看到连续的年轻gc（次要gc）暂停时间不断增加，并且超过MaxGCPauseMillis为200 ms。 The time is spent doing object copy. 做对象复制花费的时间。 Later on G1's ergo behavior kicks in to reduce eden space and copy time to meet the goal of 200 ms and over couple of hours it slowly recovers but not to it's original behavior. 后来G1的ergo行为开始减少伊甸园空间和复制时间以达到200毫秒的目标，并且在几个小时内它慢慢恢复但不是它的原始行为。 This doesn't seem like problem with GC settings or incoming traffic, as system exhibits the same behavior after FullGC. 这似乎不是GC设置或传入流量的问题，因为系统在FullGC之后表现出相同的行为。

Initially, I thought the problem was due to NUMA policy as the host that showed this behavior was 2-socket system, and also observed that host was doing lot more remote memory references after FullGC event, but now I am seeing the similar behavior for 1-socket system. 最初，我认为问题是由于NUMA策略作为显示此行为的主机是双插槽系统，并且还观察到主机在FullGC事件之后执行了更多远程内存引用，但现在我看到1的类似行为-socket系统。 Wondering if it is due to memory defrag and using LargePages would solve this, but not sure about it. 想知道它是否是由于内存碎片整理和使用LargePages会解决这个问题，但不确定。

It would be really helpful to get any insights from community, if anyone has seen similar behavior or knows what else might be going on with the host. 如果有人看到类似的行为或知道主机可能会发生什么，那么从社区获得任何见解真的很有帮助。 The host has 128gb RAM and application uses 64gb heap, GC flags are below. 主机有128GB RAM，应用程序使用64gb堆，GC标志如下。

-XX:GCLogFileSize=10485760  -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=<file path> -XX:InitialHeapSize=67108864000 -XX:+ManagementServer -XX:MaxGCPauseMillis=200  -XX:MaxHeapSize=67108864000 -XX:NumberOfGCLogFiles=15 -XX:+PrintFlagsFinal -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintTenuringDistribution -XX:+UseG1GC -XX:+UseGCLogFileRotation -XX:-UsePerfData -XX:+PrintAdaptiveSizePolicy

GC logs showing pause time before FullGC event and after including -XX:+PrintAdaptiveSizePolicy, don't see much difference. GC日志显示FullGC事件之前和包括-XX：+ PrintAdaptiveSizePolicy之后的暂停时间，没有太大的区别。

  2018-01-17T09:56:25.494-0800: 60956.918: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  150874320 bytes,  150874320 total
  - age   2:    5005336 bytes,  155879656 total
  - age   3:    4381232 bytes,  160260888 total
  - age   4:    1157480 bytes,  161418368 total
  - age   5:    1194728 bytes,  162613096 total
  - age   6:    1053664 bytes,  163666760 total
  - age   7:    1050744 bytes,  164717504 total
  - age   8:     628728 bytes,  165346232 total
  - age   9:     802400 bytes,  166148632 total
  - age  10:     850728 bytes,  166999360 total
  - age  11:     661672 bytes,  167661032 total
  - age  12:     778384 bytes,  168439416 total
  - age  13:     713024 bytes,  169152440 total
  - age  14:     754600 bytes,  169907040 total
  - age  15:     765992 bytes,  170673032 total
   60956.918: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 51732, predicted base time: 9.89 ms, remaining time: 190.11 ms, target pause time: 200.00 ms]
   60956.918: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2382 regions, survivors: 18 regions, predicted young region time: 14.35 ms]
   60956.918: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2382 regions, survivors: 18 regions, old: 0 regions, predicted pause time: 24.24 ms, target pause time: 200.00 ms]
  , 0.0292727 secs]
     [Parallel Time: 22.9 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 60956918.7, Avg: 60956919.0, Max: 60956919.3, Diff: 0.6]
        [Ext Root Scanning (ms): Min: 0.1, Avg: 0.4, Max: 0.7, Diff: 0.6, Sum: 9.8]
        [Update RS (ms): Min: 4.5, Avg: 4.8, Max: 5.9, Diff: 1.4, Sum: 119.2]
           [Processed Buffers: Min: 9, Avg: 15.6, Max: 34, Diff: 25, Sum: 391]
        [Scan RS (ms): Min: 0.2, Avg: 0.5, Max: 0.7, Diff: 0.5, Sum: 12.9]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 15.7, Avg: 16.5, Max: 16.6, Diff: 1.0, Sum: 411.3]
        [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.2]
           [Termination Attempts: Min: 1, Avg: 2.1, Max: 4, Diff: 3, Sum: 52]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 4.1]
        [GC Worker Total (ms): Min: 21.9, Avg: 22.3, Max: 22.7, Diff: 0.8, Sum: 557.5]
        [GC Worker End (ms): Min: 60956941.2, Avg: 60956941.3, Max: 60956941.5, Diff: 0.3]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.6 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.4 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.3 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.3 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 288.0M->288.0M Heap: 44.3G(62.5G)->7272.3M(62.5G)]
   [Times: user=0.59 sys=0.03, real=0.02 secs] 
  2018-01-17T09:56:27.978-0800: 60959.402: [Full GC (System.gc())  8364M->1798M(62G), 5.0412807 secs]
     [Eden: 1104.0M(37.2G)->0.0B(37.5G) Survivors: 288.0M->0.0B Heap: 8364.7M(62.5G)->1798.5M(62.5G)], [Metaspace: 25957K->25914K(28672K)]
   [Times: user=7.21 sys=0.09, real=5.04 secs] 
  2018-01-17T09:57:35.135-0800: 61026.559: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  149090328 bytes,  149090328 total
  - age   2:    6795360 bytes,  155885688 total
  - age   3:    3953152 bytes,  159838840 total
  - age   4:     813920 bytes,  160652760 total
  - age   5:    1157328 bytes,  161810088 total
  - age   6:    1193904 bytes,  163003992 total
  - age   7:     689488 bytes,  163693480 total
  - age   8:    1050744 bytes,  164744224 total
  - age   9:     628608 bytes,  165372832 total
  - age  10:     802368 bytes,  166175200 total
  - age  11:     850416 bytes,  167025616 total
  - age  12:     661360 bytes,  167686976 total
  - age  13:     778072 bytes,  168465048 total
  - age  14:     712800 bytes,  169177848 total
  - age  15:     754600 bytes,  169932448 total
   61026.559: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 21934, predicted base time: 7.23 ms, remaining time: 192.77 ms, target pause time: 200.00 ms]
   61026.559: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2400 regions, survivors: 0 regions, predicted young region time: 13.29 ms]
   61026.559: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2400 regions, survivors: 0 regions, old: 0 regions, predicted pause time: 20.52 ms, target pause time: 200.00 ms]
  , 0.0276684 secs]
     [Parallel Time: 21.1 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61026559.6, Avg: 61026559.9, Max: 61026560.1, Diff: 0.4]
        [Ext Root Scanning (ms): Min: 0.3, Avg: 0.5, Max: 0.9, Diff: 0.6, Sum: 12.9]
        [Update RS (ms): Min: 1.7, Avg: 1.9, Max: 2.2, Diff: 0.5, Sum: 47.6]
           [Processed Buffers: Min: 4, Avg: 11.9, Max: 42, Diff: 38, Sum: 297]
        [Scan RS (ms): Min: 0.2, Avg: 0.5, Max: 0.7, Diff: 0.5, Sum: 12.1]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 17.4, Avg: 17.6, Max: 17.6, Diff: 0.2, Sum: 439.1]
        [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.2]
           [Termination Attempts: Min: 2, Avg: 4.1, Max: 7, Diff: 5, Sum: 102]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 3.6]
        [GC Worker Total (ms): Min: 20.3, Avg: 20.6, Max: 21.0, Diff: 0.6, Sum: 515.6]
        [GC Worker End (ms): Min: 61026580.4, Avg: 61026580.5, Max: 61026580.6, Diff: 0.3]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.1 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.7 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.3 ms]
     [Eden: 37.5G(37.5G)->0.0B(37.2G) Survivors: 0.0B->304.0M Heap: 39.3G(62.5G)->2099.4M(62.5G)]
   [Times: user=0.56 sys=0.01, real=0.02 secs] 
  2018-01-17T09:58:19.569-0800: 61070.994: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  171868664 bytes,  171868664 total
   61070.994: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 18959, predicted base time: 6.96 ms, remaining time: 193.04 ms, target pause time: 200.00 ms]
   61070.994: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 27.61 ms]
   61070.994: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 34.57 ms, target pause time: 200.00 ms]
  , 0.0282614 secs]
     [Parallel Time: 21.7 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61070993.9, Avg: 61070994.1, Max: 61070994.4, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.8, Diff: 0.6, Sum: 11.0]
        [Update RS (ms): Min: 1.5, Avg: 1.7, Max: 2.2, Diff: 0.7, Sum: 41.6]
           [Processed Buffers: Min: 2, Avg: 10.9, Max: 45, Diff: 43, Sum: 273]
        [Scan RS (ms): Min: 0.2, Avg: 0.6, Max: 0.7, Diff: 0.6, Sum: 14.9]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 18.3, Avg: 18.4, Max: 18.5, Diff: 0.3, Sum: 460.4]
        [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
           [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 25]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 3.8]
        [GC Worker Total (ms): Min: 20.9, Avg: 21.3, Max: 21.6, Diff: 0.6, Sum: 531.9]
        [GC Worker End (ms): Min: 61071015.3, Avg: 61071015.4, Max: 61071015.5, Diff: 0.3]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.7 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.4 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.3 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->336.0M Heap: 39.3G(62.5G)->2125.0M(62.5G)]
   [Times: user=0.65 sys=0.00, real=0.03 secs] 
  2018-01-17T09:59:06.219-0800: 61117.643: [GC pause (GCLocker Initiated GC) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  169100408 bytes,  169100408 total
  - age   2:   22415336 bytes,  191515744 total
   61117.643: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 21531, predicted base time: 7.14 ms, remaining time: 192.86 ms, target pause time: 200.00 ms]
   61117.643: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2380 regions, survivors: 21 regions, predicted young region time: 17.20 ms]
   61117.643: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2380 regions, survivors: 21 regions, old: 0 regions, predicted pause time: 24.34 ms, target pause time: 200.00 ms]
  , 0.0303978 secs]
     [Parallel Time: 24.1 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61117643.5, Avg: 61117643.8, Max: 61117644.0, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.5, Max: 0.7, Diff: 0.5, Sum: 11.3]
        [Update RS (ms): Min: 1.6, Avg: 1.8, Max: 2.3, Diff: 0.8, Sum: 44.6]
           [Processed Buffers: Min: 3, Avg: 11.6, Max: 26, Diff: 23, Sum: 291]
        [Scan RS (ms): Min: 0.2, Avg: 0.6, Max: 0.7, Diff: 0.5, Sum: 14.6]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 20.4, Avg: 20.6, Max: 20.7, Diff: 0.2, Sum: 514.1]
        [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
           [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 25]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 3.5]
        [GC Worker Total (ms): Min: 23.2, Avg: 23.5, Max: 23.9, Diff: 0.6, Sum: 588.3]
        [GC Worker End (ms): Min: 61117667.2, Avg: 61117667.3, Max: 61117667.5, Diff: 0.2]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.5 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.2 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 336.0M->304.0M Heap: 39.3G(62.5G)->2100.7M(62.5G)]
   [Times: user=0.64 sys=0.01, real=0.03 secs] 
  2018-01-17T09:59:52.967-0800: 61164.391: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  164897824 bytes,  164897824 total
  - age   2:    5482152 bytes,  170379976 total
  - age   3:   19623112 bytes,  190003088 total
   61164.391: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 20596, predicted base time: 6.99 ms, remaining time: 193.01 ms, target pause time: 200.00 ms]
   61164.391: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 18.71 ms]
   61164.391: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 25.70 ms, target pause time: 200.00 ms]
  , 0.0310130 secs]
     [Parallel Time: 24.4 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61164391.2, Avg: 61164391.5, Max: 61164391.7, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.8, Diff: 0.6, Sum: 10.4]
        [Update RS (ms): Min: 1.6, Avg: 1.8, Max: 2.3, Diff: 0.7, Sum: 45.2]
           [Processed Buffers: Min: 3, Avg: 11.3, Max: 31, Diff: 28, Sum: 283]
        [Scan RS (ms): Min: 0.2, Avg: 0.6, Max: 0.7, Diff: 0.5, Sum: 14.6]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 20.9, Avg: 21.0, Max: 21.1, Diff: 0.2, Sum: 524.7]
        [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
           [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 25]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 3.7]
        [GC Worker Total (ms): Min: 23.7, Avg: 24.0, Max: 24.3, Diff: 0.7, Sum: 598.8]
        [GC Worker End (ms): Min: 61164415.3, Avg: 61164415.4, Max: 61164415.6, Diff: 0.3]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.8 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.5 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->304.0M Heap: 39.3G(62.5G)->2100.9M(62.5G)]
   [Times: user=0.70 sys=0.00, real=0.03 secs] 
  2018-01-17T10:00:39.866-0800: 61211.290: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  168482032 bytes,  168482032 total
  - age   2:    4749088 bytes,  173231120 total
  - age   3:    3178336 bytes,  176409456 total
  - age   4:   19619976 bytes,  196029432 total
   61211.290: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 22074, predicted base time: 7.07 ms, remaining time: 192.93 ms, target pause time: 200.00 ms]
   61211.290: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 19.28 ms]
   61211.290: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 26.36 ms, target pause time: 200.00 ms]
  , 0.0361588 secs]
     [Parallel Time: 29.7 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61211290.3, Avg: 61211290.5, Max: 61211290.7, Diff: 0.4]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.6, Diff: 0.4, Sum: 10.9]
        [Update RS (ms): Min: 1.8, Avg: 1.9, Max: 2.4, Diff: 0.6, Sum: 47.6]
           [Processed Buffers: Min: 5, Avg: 12.4, Max: 32, Diff: 27, Sum: 309]
        [Scan RS (ms): Min: 0.2, Avg: 0.6, Max: 0.7, Diff: 0.5, Sum: 14.9]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 26.0, Avg: 26.1, Max: 26.2, Diff: 0.2, Sum: 652.8]
        [Termination (ms): Min: 0.1, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 3.6]
           [Termination Attempts: Min: 40, Avg: 52.2, Max: 65, Diff: 25, Sum: 1305]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 3.4]
        [GC Worker Total (ms): Min: 29.1, Avg: 29.3, Max: 29.6, Diff: 0.6, Sum: 733.3]
        [GC Worker End (ms): Min: 61211319.7, Avg: 61211319.8, Max: 61211319.9, Diff: 0.2]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.8 ms]
     [Other: 3.6 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.2 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->304.0M Heap: 39.3G(62.5G)->2093.9M(62.5G)]
   [Times: user=0.78 sys=0.01, real=0.03 secs] 
  2018-01-17T10:01:24.926-0800: 61256.351: [GC pause (GCLocker Initiated GC) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  164765392 bytes,  164765392 total
  - age   2:    3962056 bytes,  168727448 total
  - age   3:    3375800 bytes,  172103248 total
  - age   4:    3152672 bytes,  175255920 total
  - age   5:   19567808 bytes,  194823728 total
   61256.351: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 26856, predicted base time: 7.46 ms, remaining time: 192.54 ms, target pause time: 200.00 ms]
   61256.351: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2382 regions, survivors: 19 regions, predicted young region time: 22.07 ms]
   61256.351: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2382 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 29.53 ms, target pause time: 200.00 ms]
  , 0.0525081 secs]
     [Parallel Time: 46.1 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61256351.0, Avg: 61256351.3, Max: 61256351.5, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.7, Diff: 0.5, Sum: 10.6]
        [Update RS (ms): Min: 2.0, Avg: 2.2, Max: 2.5, Diff: 0.5, Sum: 55.8]
           [Processed Buffers: Min: 3, Avg: 11.6, Max: 39, Diff: 36, Sum: 290]
        [Scan RS (ms): Min: 0.2, Avg: 0.5, Max: 0.7, Diff: 0.4, Sum: 13.6]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 41.5, Avg: 41.6, Max: 41.8, Diff: 0.3, Sum: 1041.1]
        [Termination (ms): Min: 0.6, Avg: 0.7, Max: 0.8, Diff: 0.2, Sum: 16.8]
           [Termination Attempts: Min: 234, Avg: 259.0, Max: 289, Diff: 55, Sum: 6474]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 3.6]
        [GC Worker Total (ms): Min: 45.4, Avg: 45.7, Max: 46.0, Diff: 0.6, Sum: 1141.5]
        [GC Worker End (ms): Min: 61256396.8, Avg: 61256396.9, Max: 61256397.1, Diff: 0.2]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.7 ms]
     [Other: 3.6 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.3 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->304.0M Heap: 39.3G(62.5G)->2093.9M(62.5G)]
   [Times: user=1.23 sys=0.00, real=0.05 secs] 
  2018-01-17T10:02:12.464-0800: 61303.888: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  169945088 bytes,  169945088 total
  - age   2:    4935304 bytes,  174880392 total
  - age   3:    2952560 bytes,  177832952 total
  - age   4:    3375096 bytes,  181208048 total
  - age   5:    3152384 bytes,  184360432 total
  - age   6:   19545992 bytes,  203906424 total
   61303.888: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 25648, predicted base time: 7.29 ms, remaining time: 192.71 ms, target pause time: 200.00 ms]
   61303.888: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 30.07 ms]
   61303.888: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 37.36 ms, target pause time: 200.00 ms]
  , 0.0604556 secs]
     [Parallel Time: 53.9 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61303888.2, Avg: 61303888.4, Max: 61303888.6, Diff: 0.4]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.7, Diff: 0.4, Sum: 10.8]
        [Update RS (ms): Min: 2.0, Avg: 2.2, Max: 2.8, Diff: 0.8, Sum: 55.0]
           [Processed Buffers: Min: 5, Avg: 12.0, Max: 49, Diff: 44, Sum: 301]
        [Scan RS (ms): Min: 0.2, Avg: 0.6, Max: 0.8, Diff: 0.6, Sum: 15.6]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 49.1, Avg: 49.3, Max: 49.5, Diff: 0.4, Sum: 1232.0]
        [Termination (ms): Min: 0.6, Avg: 0.8, Max: 1.0, Diff: 0.3, Sum: 19.1]
           [Termination Attempts: Min: 292, Avg: 317.8, Max: 351, Diff: 59, Sum: 7946]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 3.8]
        [GC Worker Total (ms): Min: 53.2, Avg: 53.5, Max: 53.8, Diff: 0.6, Sum: 1336.5]
        [GC Worker End (ms): Min: 61303941.7, Avg: 61303941.9, Max: 61303942.0, Diff: 0.3]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.8 ms]
     [Other: 3.7 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.2 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->304.0M Heap: 39.2G(62.5G)->2094.1M(62.5G)]
   [Times: user=1.38 sys=0.01, real=0.07 secs] 
  2018-01-17T10:02:59.224-0800: 61350.648: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  165515088 bytes,  165515088 total
  - age   2:    5810696 bytes,  171325784 total
  - age   3:    3680000 bytes,  175005784 total
  - age   4:    2952376 bytes,  177958160 total
  - age   5:    3374960 bytes,  181333120 total
  - age   6:    3152352 bytes,  184485472 total
  - age   7:   19542960 bytes,  204028432 total
   61350.648: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 26349, predicted base time: 7.38 ms, remaining time: 192.62 ms, target pause time: 200.00 ms]
   61350.648: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 37.34 ms]
   61350.648: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 44.72 ms, target pause time: 200.00 ms]
  , 0.0681355 secs]
     [Parallel Time: 61.7 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61350648.3, Avg: 61350648.6, Max: 61350648.8, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.1, Avg: 0.4, Max: 0.6, Diff: 0.5, Sum: 8.9]
        [Update RS (ms): Min: 2.2, Avg: 2.3, Max: 2.8, Diff: 0.6, Sum: 58.1]
           [Processed Buffers: Min: 4, Avg: 12.3, Max: 27, Diff: 23, Sum: 308]
        [Scan RS (ms): Min: 0.2, Avg: 0.5, Max: 0.7, Diff: 0.5, Sum: 13.4]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 56.6, Avg: 56.8, Max: 57.0, Diff: 0.4, Sum: 1421.1]
        [Termination (ms): Min: 0.8, Avg: 1.0, Max: 1.2, Diff: 0.4, Sum: 24.2]
           [Termination Attempts: Min: 333, Avg: 397.2, Max: 450, Diff: 117, Sum: 9931]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.2, Sum: 3.6]
        [GC Worker Total (ms): Min: 60.9, Avg: 61.2, Max: 61.5, Diff: 0.6, Sum: 1529.2]
        [GC Worker End (ms): Min: 61350709.6, Avg: 61350709.7, Max: 61350709.8, Diff: 0.2]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.8 ms]
     [Other: 3.5 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.2 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->304.0M Heap: 39.2G(62.5G)->2102.0M(62.5G)]
   [Times: user=1.59 sys=0.00, real=0.07 secs] 
  2018-01-17T10:03:44.854-0800: 61396.278: [GC pause (G1 Evacuation Pause) (young)
  Desired survivor size 2516582400 bytes, new threshold 15 (max 15)
  - age   1:  164753576 bytes,  164753576 total
  - age   2:    4971568 bytes,  169725144 total
  - age   3:    5802160 bytes,  175527304 total
  - age   4:    3678784 bytes,  179206088 total
  - age   5:    2952376 bytes,  182158464 total
  - age   6:    3374960 bytes,  185533424 total
  - age   7:    3152352 bytes,  188685776 total
  - age   8:   19525304 bytes,  208211080 total
   61396.278: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 27515, predicted base time: 7.50 ms, remaining time: 192.50 ms, target pause time: 200.00 ms]
   61396.278: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 2381 regions, survivors: 19 regions, predicted young region time: 44.05 ms]
   61396.278: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 2381 regions, survivors: 19 regions, old: 0 regions, predicted pause time: 51.55 ms, target pause time: 200.00 ms]
  , 0.0757171 secs]
     [Parallel Time: 69.3 ms, GC Workers: 25]
        [GC Worker Start (ms): Min: 61396278.1, Avg: 61396278.3, Max: 61396278.6, Diff: 0.5]
        [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.7, Diff: 0.5, Sum: 10.4]
        [Update RS (ms): Min: 2.3, Avg: 2.4, Max: 2.8, Diff: 0.5, Sum: 61.2]
           [Processed Buffers: Min: 5, Avg: 12.2, Max: 29, Diff: 24, Sum: 305]
        [Scan RS (ms): Min: 0.3, Avg: 0.5, Max: 0.7, Diff: 0.4, Sum: 13.5]
        [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
        [Object Copy (ms): Min: 63.7, Avg: 64.1, Max: 64.3, Diff: 0.6, Sum: 1601.9]
        [Termination (ms): Min: 1.1, Avg: 1.2, Max: 1.5, Diff: 0.5, Sum: 30.1]
           [Termination Attempts: Min: 453, Avg: 502.3, Max: 540, Diff: 87, Sum: 12557]
        [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 3.5]
        [GC Worker Total (ms): Min: 68.6, Avg: 68.8, Max: 69.2, Diff: 0.7, Sum: 1720.8]
        [GC Worker End (ms): Min: 61396347.1, Avg: 61396347.2, Max: 61396347.3, Diff: 0.2]
     [Code Root Fixup: 0.1 ms]
     [Code Root Purge: 0.0 ms]
     [Clear CT: 2.8 ms]
     [Other: 3.6 ms]
        [Choose CSet: 0.0 ms]
        [Ref Proc: 0.3 ms]
        [Ref Enq: 0.0 ms]
        [Redirty Cards: 0.2 ms]
        [Humongous Register: 0.1 ms]
        [Humongous Reclaim: 0.0 ms]
        [Free CSet: 2.3 ms]
     [Eden: 37.2G(37.2G)->0.0B(37.2G) Survivors: 304.0M->288.0M Heap: 39.3G(62.5G)->2086.3M(62.5G)]
   [Times: user=1.79 sys=0.00, real=0.08 secs]

Answer 1

I suspect that the Full GC cleans the young generation which in turn changes tenuring since there will not be any object with an age > 1 at the first young collection after the full GC which in turn affects heuristics. 我怀疑Full GC清洁了年轻一代，而年轻一代又改变了年龄，因为在完整的GC后第一个年轻的收集品中没有任何年龄> 1的物体反过来影响启发式。

You should try disabling System.gc() via -XX:+DisableExplicitGC or at least let set -XX:+ExplicitGCInvokesConcurrent so it invokes a concurrent cycle and mixed collections instead of a Full GC. 您应该尝试通过-XX:+DisableExplicitGC禁用System.gc() -XX:+DisableExplicitGC或至少让set -XX:+ExplicitGCInvokesConcurrent以便它调用并发循环和混合集合而不是Full GC。

Additionally you might want to turn on -XX:+PrintAdaptiveSizePolicy to see how it chooses which regions to collect. 此外，您可能需要打开-XX:+PrintAdaptiveSizePolicy以查看它如何选择要收集的区域。

wondering if it is due to memory defrag 想知道是否是由于内存碎片整理

You could test that by triggering it manually . 您可以通过手动触发来测试它。

在全GC事件发生后，G1收集器采用长年轻（轻微gc）暂停时间

问题描述

1 个解决方案

解决方案1
0 2018-01-16 21:20:50

在全GC事件发生后，G1收集器采用长年轻（轻微gc）暂停时间

问题描述

1 个解决方案

解决方案1 0 2018-01-16 21:20:50

解决方案1
0 2018-01-16 21:20:50