Garbage collection G1如何确定年轻区域的数量？

有人能解释一下G1收集器是如何确定年轻区域的数量的吗？G1论文指出，“我们通过历史平均值跟踪完全年轻的收藏品的固定成本和每个地区的成本，并使用这些估计值确定在完全年轻的疏散暂停之间分配的年轻地区的数量”，但没有详细说明

例如，给定以下GC日志，预测的年轻区域时间意味着什么，如何计算？伊甸园和幸存者是如何计算的

    2015-12-30T08:04:21.124+0000: 10.424: [GC pause (young) 10.424: [G1Ergonomics (CSet Construction) start choosing CSet, _pending_cards: 281, predicted base time: 17.05 ms, remaining time: 182.95 ms, target pause time: 200.00 ms]
 10.424: [G1Ergonomics (CSet Construction) add young regions to CSet, eden: 155 regions, survivors: 5 regions, predicted young region time: 7335.19 ms]
 10.424: [G1Ergonomics (CSet Construction) finish choosing CSet, eden: 155 regions, survivors: 5 regions, old: 0 regions, predicted pause time: 7352.24 ms, target pause time: 200.00 ms]
2015-12-30T08:04:21.171+0000: 10.472: [SoftReference, 0 refs, 0.0000490 secs]2015-12-30T08:04:21.172+0000: 10.472: [WeakReference, 617 refs, 0.0000780 secs]2015-12-30T08:04:21.172+0000: 10.472: [FinalReference, 360 refs, 0.0004730 secs]2015-12-30T08:04:21.172+0000: 10.472: [PhantomReference, 1 refs, 45 refs, 0.0000210 secs]2015-12-30T08:04:21.172+0000: 10.472: [JNI Weak Reference, 0.0000120 secs], 0.0494460 secs]
   [Parallel Time: 47.1 ms, GC Workers: 13]
      [GC Worker Start (ms): Min: 10424.3, Avg: 10424.4, Max: 10424.5, Diff: 0.2]
      [Ext Root Scanning (ms): Min: 1.2, Avg: 1.6, Max: 2.0, Diff: 0.8, Sum: 21.2]
      [Update RS (ms): Min: 0.0, Avg: 0.0, Max: 0.0, Diff: 0.0, Sum: 0.0]
         [Processed Buffers: Min: 0, Avg: 0.6, Max: 8, Diff: 8, Sum: 8]
      [Scan RS (ms): Min: 0.0, Avg: 0.0, Max: 0.3, Diff: 0.2, Sum: 0.5]
      [Code Root Scanning (ms): Min: 0.0, Avg: 0.0, Max: 0.3, Diff: 0.3, Sum: 0.3]
      [Object Copy (ms): Min: 44.4, Avg: 44.7, Max: 45.0, Diff: 0.6, Sum: 581.5]
      [Termination (ms): Min: 0.0, Avg: 0.2, Max: 0.3, Diff: 0.3, Sum: 3.0]
      [GC Worker Other (ms): Min: 0.0, Avg: 0.0, Max: 0.1, Diff: 0.1, Sum: 0.4]
      [GC Worker Total (ms): Min: 46.5, Avg: 46.7, Max: 46.8, Diff: 0.2, Sum: 606.9]
      [GC Worker End (ms): Min: 10471.1, Avg: 10471.1, Max: 10471.1, Diff: 0.1]
   [Code Root Fixup: 0.1 ms]
   [Code Root Migration: 0.3 ms]
   [Clear CT: 0.5 ms]
   [Other: 1.5 ms]
      [Choose CSet: 0.0 ms]
      [Ref Proc: 1.1 ms]
      [Ref Enq: 0.0 ms]
      [Free CSet: 0.3 ms]
   [Eden: 4960.0M(4960.0M)->0.0B(4800.0M) Survivors: 160.0M->320.0M Heap: 5142.0M(100.0G)->345.4M(100.0G)]
 [Times: user=0.60 sys=0.01, real=0.05 secs]