JVM学习之G1回收器

矫情吗；* 2022-05-20 06:40 202阅读 0赞

![这里写图片描述][70]  
G1 收集器不区分年轻代或老年代，所有的堆内存就是一块。但是会划分出不同的子区域。

虽然在G1收集器里面将整个内存区域都混合在了一起，但是其本身在小范围内依然进行了年轻代和老年代的区分，就是说依然会采用不同的GC策略来处理不同的内存域。  
![这里写图片描述][70 1]

G1 回收流程：

*  年轻代的处理流程  
    ![这里写图片描述][70 2]  
    ![这里写图片描述][70 3]
    
     *  1、先对内存空间进行子区域划分。
     *  2、对子区域中需要清理（包括一些满的，未满的子区域）的年轻代内存空间进行标记。
     *  3、对被标记的区域进行清空，一些年轻代中继续使用的对象copy到老年代中。
    
    总结：所有的垃圾内存的保存区域有可能会被清空后重新分配。
 *  老年代的处理流程  
    ![这里写图片描述][70 4]  
    ![这里写图片描述][70 5]  
    ![这里写图片描述][70 6]  
    ![这里写图片描述][70 7]  
    ![这里写图片描述][70 8]  
    ![这里写图片描述][70 9]
    
    任何时候如果想要标注老年代的垃圾内存空间，都需要进行一些暂停操作，而G1的最大好处在于它不用进行全内存扫描，只需要按照区域来进行扫描。
    
     *  1、先对内存空间进行子区域划分并标记。
     *  2、然后进行根区域扫描，对子区域中需要清理的老年代内存空间进行并发标记。
     *  3、然后进行重新标记，这个时候会清理并发标记阶段被标记的内存空间。
     *  4、重新标记之后，还要对一些年轻代内存空间使用年轻代的G1处理流程进行清理。
     *  5、在使用年轻代的处理流程之后，将内存空间重新整理分配，这样整个内存空间就被很高效的清理。

G1收集器参数配置  
![这里写图片描述][70 10]

观察G1回收操作：

// 测试代码
    public static void main(String[] args) {
        String str = "ShowG1GC";
        while (true) {
            str += str;
            str.intern();
        }
    }

VM参数：**-Xmx10m -Xms10m -XX:+UseG1GC -XX:+PrintGCDetails**

运行结果：从下面运行结果可以观察出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

[70]: /images/20220520/1f1b8f2f8a734df5884399456c1921b5.png
[70 1]: /images/20220520/be67623c65b24e07b01e0c7c51b861d1.png
[70 2]: /images/20220520/ef8bb2fe48894fbbb2d7d82d9bd65793.png
[70 3]: /images/20220520/325e76df56a24f99874bcb616d4b7a70.png
[70 4]: /images/20220520/a5b3f6add1de4d2490f33346c6080eb2.png
[70 5]: /images/20220520/6d3b4252ce7241299e2eb959c66c62f3.png
[70 6]: /images/20220520/7782302b903b41d5b3cb40a5570a073e.png
[70 7]: /images/20220520/32df4382125c43d0951f5bc78547bb5c.png
[70 8]: /images/20220520/d8172c1c5f174caba43142d81057074f.png
[70 9]: /images/20220520/01092ccec6f4441da5d4e8cd71f1db55.png
[70 10]: /images/20220520/8f3c1596926c4165a9a4f1f651cba50c.png