JVM學習之G1回收器

原創 轻描淡写灬 2018-08-22 18:16
版權聲明：本文爲博主原創文章，未經博主允許不得轉載。 https://blog.csdn.net/qq_34560242/article/details/81038515

這裏寫圖片描述
G1 收集器不區分年輕代或老年代，所有的堆內存就是一塊。但是會劃分出不同的子區域。

雖然在G1收集器裏面將整個內存區域都混合在了一起，但是其本身在小範圍內依然進行了年輕代和老年代的區分，就是說依然會採用不同的GC策略來處理不同的內存域。
這裏寫圖片描述

G1 回收流程：

  • 年輕代的處理流程
    這裏寫圖片描述
    這裏寫圖片描述

    • 1、先對內存空間進行子區域劃分。
    • 2、對子區域中需要清理（包括一些滿的，未滿的子區域）的年輕代內存空間進行標記。
    • 3、對被標記的區域進行清空，一些年輕代中繼續使用的對象copy到老年代中。

    總結：所有的垃圾內存的保存區域有可能會被清空後重新分配。

  • 老年代的處理流程
    這裏寫圖片描述
    這裏寫圖片描述
    這裏寫圖片描述
    這裏寫圖片描述
    這裏寫圖片描述
    這裏寫圖片描述

    任何時候如果想要標註老年代的垃圾內存空間，都需要進行一些暫停操作，而G1的最大好處在於它不用進行全內存掃描，只需要按照區域來進行掃描。

    • 1、先對內存空間進行子區域劃分並標記。
    • 2、然後進行根區域掃描，對子區域中需要清理的老年代內存空間進行併發標記。
    • 3、然後進行重新標記，這個時候會清理併發標記階段被標記的內存空間。
    • 4、重新標記之後，還要對一些年輕代內存空間使用年輕代的G1處理流程進行清理。
    • 5、在使用年輕代的處理流程之後，將內存空間重新整理分配，這樣整個內存空間就被很高效的清理。

G1收集器參數配置
這裏寫圖片描述

觀察G1回收操作：

// 測試代碼
public static void main(String[] args) {
    String str = "ShowG1GC";
    while (true) {
        str += str;
        str.intern();
    }
}

VM參數：-Xmx10m -Xms10m -XX:+UseG1GC -XX:+PrintGCDetails

運行結果：從下面運行結果可以觀察出G1回收器的大概流程。

[GC pause (G1 Humongous Allocation) (young) (initial-mark) (to-space exhausted), 0.0039032 secs]
   [Parallel Time: 2.5 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 201.6, Avg: 201.7, Max: 202.0, Diff: 0.3]
      [Ext Root Scanning (ms): Min: 0.2, Avg: 0.4, Max: 0.9, Diff: 0.7, Sum: 3.4]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.0, Max: 0, Diff: 0, Sum: 0]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 1.5, Avg: 1.8, Max: 2.0, Diff: 0.5, Sum: 14.4]
      [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: 17]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.1, Max: 0.4, Diff: 0.3, Sum: 0.8]
      [GC Worker Total (ms): Min: 2.1, Avg: 2.4, Max: 2.4, Diff: 0.3, Sum: 18.9]
      [GC Worker End (ms): Min: 204.1, Avg: 204.1, Max: 204.1, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 1.4 ms]
      [Evacuation Failure: 1.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 4096.0K(6144.0K)->0.0B(1024.0K) Survivors: 0.0B->1024.0K Heap: 6400.1K(10.0M)->5632.0K(10.0M)]
 [Times: user=0.02 sys=0.00, real=0.00 secs] 
[GC concurrent-root-region-scan-start]
[GC pause (G1 Humongous Allocation) (young)[GC concurrent-root-region-scan-end, 0.0006530 secs]
[GC concurrent-mark-start]
, 0.0018286 secs]
   [Root Region Scan Waiting: 0.6 ms]
   [Parallel Time: 1.0 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 206.3, Avg: 206.6, Max: 207.2, Diff: 0.9]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 0.9]
      [Update RS (ms): Min: 0.0, Avg: 0.1, Max: 0.4, Diff: 0.4, Sum: 1.0]
         [Processed Buffers: Min: 0, Avg: 0.5, Max: 1, Diff: 1, Sum: 4]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.4, Max: 0.7, Diff: 0.7, Sum: 3.0]
      [Termination (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.5]
         [Termination Attempts: Min: 1, Avg: 8.8, Max: 18, Diff: 17, Sum: 70]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.7, Max: 0.9, Diff: 0.9, Sum: 5.4]
      [GC Worker End (ms): Min: 207.2, Avg: 207.2, Max: 207.3, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 1024.0K->0.0B Heap: 5632.0K(10.0M)->5636.5K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-mark-end, 0.0020078 secs]
[GC remark [Finalize Marking, 0.0001069 secs] [GC ref-proc, 0.0001377 secs] [Unloading, 0.0005376 secs], 0.0008904 secs]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Evacuation Pause) (young), 0.0006539 secs]
   [Parallel Time: 0.4 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 212.3, Avg: 212.4, Max: 212.5, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.7]
      [Update RS (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 1.0]
         [Processed Buffers: Min: 0, Avg: 0.9, Max: 1, Diff: 1, Sum: 7]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.1]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.3, Avg: 0.4, Max: 0.4, Diff: 0.2, Sum: 2.8]
      [GC Worker End (ms): Min: 212.7, Avg: 212.7, Max: 212.7, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 0.0B->0.0B Heap: 6660.6K(10.0M)->6660.6K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC cleanup 6660K->6660K(10M), 0.0002010 secs]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Evacuation Pause) (young), 0.0004170 secs]
   [Parallel Time: 0.2 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 213.4, Avg: 213.4, Max: 213.6, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.7]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.2]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.0]
      [GC Worker End (ms): Min: 213.6, Avg: 213.6, Max: 213.6, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.1 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 0.0B->0.0B Heap: 6660.6K(10.0M)->6660.6K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[Full GC (Allocation Failure)  6660K->1781K(10M), 0.0031454 secs]
   [Eden: 0.0B(1024.0K)->0.0B(3072.0K) Survivors: 0.0B->0.0B Heap: 6660.6K(10.0M)->1781.1K(10.0M)], [Metaspace: 3440K->3440K(1056768K)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Humongous Allocation) (young) (initial-mark), 0.0006543 secs]
   [Parallel Time: 0.4 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 218.9, Avg: 219.0, Max: 219.1, Diff: 0.3]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 1.2]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.1, Max: 1, Diff: 1, Sum: 1]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.2]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.1, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 1.5]
      [GC Worker End (ms): Min: 219.2, Avg: 219.2, Max: 219.2, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.1 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 1024.0K(3072.0K)->0.0B(2048.0K) Survivors: 0.0B->1024.0K Heap: 2866.6K(10.0M)->2807.1K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-root-region-scan-start]
[GC pause (G1 Humongous Allocation) (young)[GC concurrent-root-region-scan-end, 0.0001694 secs]
[GC concurrent-mark-start]
, 0.0005641 secs]
   [Root Region Scan Waiting: 0.1 ms]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 219.9, Avg: 219.9, Max: 220.1, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.7]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.2]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.0]
      [GC Worker End (ms): Min: 220.1, Avg: 220.1, Max: 220.1, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.1 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(2048.0K)->0.0B(2048.0K) Survivors: 1024.0K->1024.0K Heap: 2807.1K(10.0M)->2807.1K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[Full GC (Allocation Failure)  2807K->2739K(10M), 0.0037505 secs]
   [Eden: 0.0B(2048.0K)->0.0B(3072.0K) Survivors: 1024.0K->0.0B Heap: 2807.1K(10.0M)->2739.9K(10.0M)], [Metaspace: 3440K->3440K(1056768K)]
 [Times: user=0.01 sys=0.00, real=0.00 secs] 
[GC concurrent-mark-abort]
[GC pause (G1 Humongous Allocation) (young) (initial-mark), 0.0007330 secs]
   [Parallel Time: 0.4 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 225.8, Avg: 225.9, Max: 226.0, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 1.3]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 2, Diff: 2, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.4]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.1, Avg: 0.2, Max: 0.4, Diff: 0.3, Sum: 1.8]
      [GC Worker End (ms): Min: 226.1, Avg: 226.1, Max: 226.2, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.3 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.1 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 1024.0K(3072.0K)->0.0B(1024.0K) Survivors: 0.0B->1024.0K Heap: 4910.8K(10.0M)->3765.9K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-root-region-scan-start]
[GC pause (G1 Humongous Allocation) (young)[GC concurrent-root-region-scan-end, 0.0001381 secs]
[GC concurrent-mark-start]
, 0.0005863 secs]
   [Root Region Scan Waiting: 0.0 ms]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 226.8, Avg: 226.9, Max: 227.0, Diff: 0.3]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 0.5]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.3]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.3, Diff: 0.3, Sum: 0.9]
      [GC Worker End (ms): Min: 227.0, Avg: 227.1, Max: 227.1, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.1 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 1024.0K->1024.0K Heap: 3765.9K(10.0M)->3765.9K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-mark-end, 0.0026472 secs]
[GC remark [Finalize Marking, 0.0001172 secs] [GC ref-proc, 0.0001433 secs] [Unloading, 0.0006440 secs], 0.0010289 secs]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Evacuation Pause) (young) (to-space exhausted), 0.0005149 secs]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 235.8, Avg: 235.9, Max: 236.0, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 0.6]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.1]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.3]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.1]
      [GC Worker End (ms): Min: 236.0, Avg: 236.0, Max: 236.0, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.2 ms]
      [Evacuation Failure: 0.0 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 1024.0K->0.0B Heap: 5813.9K(10.0M)->5813.9K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Evacuation Pause) (young), 0.0004302 secs]
   [Parallel Time: 0.2 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 236.4, Avg: 236.5, Max: 236.6, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.5]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.4, Max: 1, Diff: 1, Sum: 3]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.2]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 0.8]
      [GC Worker End (ms): Min: 236.6, Avg: 236.6, Max: 236.6, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.0 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 0.0B->0.0B Heap: 5813.9K(10.0M)->5813.9K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC cleanup 5813K->5813K(10M), 0.0002160 secs]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Evacuation Pause) (young), 0.0004593 secs]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 237.3, Avg: 237.4, Max: 237.5, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.1, Diff: 0.1, Sum: 0.7]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.3]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.0]
      [GC Worker End (ms): Min: 237.5, Avg: 237.5, Max: 237.5, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.1 ms]
   [Other: 0.1 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 0.0B->0.0B Heap: 5813.9K(10.0M)->5813.9K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[Full GC (Allocation Failure)  5813K->2739K(10M), 0.0027237 secs]
   [Eden: 0.0B(1024.0K)->0.0B(4096.0K) Survivors: 0.0B->0.0B Heap: 5813.9K(10.0M)->2739.4K(10.0M)], [Metaspace: 3440K->3440K(1056768K)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC pause (G1 Humongous Allocation) (young) (initial-mark), 0.0004657 secs]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 241.4, Avg: 241.5, Max: 241.6, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 1.1]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.1, Max: 1, Diff: 1, Sum: 1]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.3]
         [Termination Attempts: Min: 1, Avg: 1.1, Max: 2, Diff: 1, Sum: 9]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.1, Avg: 0.2, Max: 0.2, Diff: 0.2, Sum: 1.5]
      [GC Worker End (ms): Min: 241.6, Avg: 241.7, Max: 241.7, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.0 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 1024.0K(4096.0K)->0.0B(3072.0K) Survivors: 0.0B->1024.0K Heap: 2821.3K(10.0M)->2741.4K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-root-region-scan-start]
[GC concurrent-root-region-scan-end, 0.0000633 secs]
[GC concurrent-mark-start]
[GC pause (G1 Humongous Allocation) (young), 0.0004922 secs]
   [Parallel Time: 0.3 ms, GC Workers: 8]
      [GC Worker Start (ms): Min: 243.2, Avg: 243.3, Max: 243.4, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 0.0, Avg: 0.1, Max: 0.2, Diff: 0.2, Sum: 0.9]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.3, Max: 1, Diff: 1, Sum: 2]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Object Copy (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [Termination (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.3]
         [Termination Attempts: Min: 1, Avg: 1.0, Max: 1, Diff: 0, Sum: 8]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
      [GC Worker Total (ms): Min: 0.0, Avg: 0.2, Max: 0.2, Diff: 0.2, Sum: 1.3]
      [GC Worker End (ms): Min: 243.4, Avg: 243.4, Max: 243.4, Diff: 0.0]
   [Code Root Fixup: 0.0 ms]
   [Code Root Purge: 0.0 ms]
   [Clear CT: 0.0 ms]
   [Other: 0.2 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 0.1 ms]
      [Ref Enq: 0.0 ms]
      [Redirty Cards: 0.0 ms]
      [Humongous Register: 0.0 ms]
      [Humongous Reclaim: 0.0 ms]
      [Free CSet: 0.0 ms]
   [Eden: 0.0B(3072.0K)->0.0B(3072.0K) Survivors: 1024.0K->1024.0K Heap: 4789.4K(10.0M)->4789.4K(10.0M)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[Full GC (Allocation Failure)  4789K->4787K(10M), 0.0028003 secs]
   [Eden: 0.0B(3072.0K)->0.0B(1024.0K) Survivors: 1024.0K->0.0B Heap: 4789.4K(10.0M)->4787.4K(10.0M)], [Metaspace: 3440K->3440K(1056768K)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[Full GC (Allocation Failure) Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:3332)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:124)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:448)
    at java.lang.StringBuilder.append(StringBuilder.java:136)
    at com.zfspace.test.TestG1.main(TestG1.java:8)
 4787K->4769K(10M), 0.0035183 secs]
   [Eden: 0.0B(1024.0K)->0.0B(1024.0K) Survivors: 0.0B->0.0B Heap: 4787.4K(10.0M)->4769.3K(10.0M)], [Metaspace: 3440K->3440K(1056768K)]
 [Times: user=0.00 sys=0.00, real=0.00 secs] 
[GC concurrent-mark-abort]
Heap
 garbage-first heap   total 10240K, used 4769K [0x00000000ff600000, 0x00000000ff700050, 0x0000000100000000)
  region size 1024K, 1 young (1024K), 0 survivors (0K)
 Metaspace       used 3472K, capacity 4496K, committed 4864K, reserved 1056768K
  class space    used 379K, capacity 388K, committed 512K, reserved 1048576K
發表評論
所有評論
還沒有人評論，想成為第一個評論的人麼? 請在上方評論欄輸入並且點擊發布.
相關文章

java線程併發庫

  ThreadLocal的使用，，，實際上相當於維護了一個Map，其中以鍵值對的形式，存儲了某一個數據被多個線程訪問所對應的值。當然這個數據只能有

xinyetonghua 2020-07-08 12:36:33

分佈式系統各個節點狀態如何同步？淺談一下

寫在前面：2020年面試必備的Java後端進階面試題總結了一份複習指南在Github上，內容詳細，圖文並茂，有需要學習的朋友可以Star一下！ GitHub地址：https://github.com/abel-max/Java-S

毛发旺盛的程序员 2020-07-08 12:27:30

ZooKeeper 一致性協議 ZAB 原理，瞭解一下

一致性協議有很多種，比如 Paxos，Raft，2PC，3PC等等，在這講一種協議，ZAB 協議，該協議應該是所有一致性協議中生產環境中應用最多的了。爲什麼？因爲它是爲 Zookeeper 設計的分佈式一致性協議！ 1. 什麼是

毛发旺盛的程序员 2020-07-08 12:27:20

Spring中Transactional 失效的解決方案，讓我們一起探討一下

寫在前面：2020年面試必備的Java後端進階面試題總結了一份複習指南在Github上，內容詳細，圖文並茂，有需要學習的朋友可以Star一下！ GitHub地址：https://github.com/abel-max/Java-S

毛发旺盛的程序员 2020-07-08 12:27:20

太狠了,Spring全家桶筆記,一站式通關全攻略,已入職某廠漲薪18K

Spring 早已成爲 Java 後端開發事實上的行業標準，無數的公司選擇 Spring 作爲基礎的開發框架，大部分Java 後端程序員在日常工作中也會接觸到 Spring ，因此，如何用好 Spring ，也就成爲 Java

毛发旺盛的程序员 2020-07-08 12:27:20

java中的NAN和INFINITY java中的NAN和INFINITY

    java中的NAN和INFINITY   java浮點數運算中有兩個特殊的情況：NAN、INFINITY。 1、INFINITY： 在浮點數運算時，有時我們會遇到除數爲0的情況，那java是如何解決的呢？ 我們知道，在整型運算中

a318013800 2021-11-28 13:09:28

【Java 小白菜入門筆記 2.2】常用的類和方法

Array Array 含有sort、fill、equals、BinarySearch等方法 import java.util.Arrays; import java.util.Random; public class Arra

江户川柯壮 2020-07-08 12:39:29

springboot增量打包更新--靜態資源分離打包

springboot部署打包爲jar，一般都是全量打包，jar包的大小通常都是超過100M的，並且在進行一般的頁面html微調、js修改、img替換、css樣式修改時也需要重新打包進行部署；每次微小的調整都需要重新打包就太煩了，一

CNOYG 2020-07-08 12:39:29

增加FastDfs多文件存儲路徑

項目需要增加聊天會話功能，涉及到上傳語音圖片等信息。考慮新增一個目錄，所有相關文件存在一個相同的目錄中。因此需要對原項目增加一個存儲的路徑。以前的項目因爲只有一個路徑，且已經運行中。走了些彎路，僅此記錄操作過程。nginx version

pengdayong77 2020-07-08 12:37:23

JSONArray指定日期的反序列化

 JSONArray序列化日期最初用到， 這個是全局設置，會有風險。     String[] dateFormats = new String[] {"yyyyMMdd"};                 JSONUtils.getM

pengdayong77 2020-07-08 12:37:23

java緩存對象，使之不需要每次都從數據庫中獲取,以提高程序性能

直接上源碼，定義一個抽象類，必須實現get方法。該方法是用來獲取需要緩存的對象的。  import java.util.HashMap; import java.util.Map; /** * 用於從數據庫中獲取相應值的緩存類 *

pengdayong77 2020-07-08 12:37:23

類加載和類實例化

Java程序中對類的使用方式分爲兩類 ：主動使用和被動使用 主動使用： 創建類的實例 訪問某個類或接口的靜態變量，或者對該靜態變量賦值 調用類的靜態方法 反射 初始化一個類的子類 java虛擬機啓動時被標明爲啓動類的類 從JDK

吃酒忘情殇 2020-07-08 12:36:21

大數據入門（七）win10上eclipse使用Hadoop的配置

目錄工具eclipse的Hadoop環境配置參考 系列： 大數據入門（一）環境搭建，VMware15+CentOS8.1 配置 https://blog.csdn.net/qq_34391511/article/details/1

33 Audrey 2020-07-08 12:35:23

Java動態綁定機制經典案列理解

如題，直接帶入案例進行理解Java的動態綁定機制，不多說直接上代碼了。 package one; public class JavaTest { public static void main(String[] args

柘月十七 2020-07-08 12:33:16

阿里年薪破百架構師推薦：鳥哥的Linux私房菜，搭配面試題，真香

在Linux實操的過程中，你是否有過這些疑問： 如何提取日誌中含有關鍵字的指定行，上一行或上幾行？ ln 做了符號鏈接，對符號鏈接進行權限修改，原文件是否會受到影響？ Shell 腳本里有很多特殊符號，到底該怎麼用？網上流傳的

毛发旺盛的程序员 2020-07-08 12:27:30