GC s1 always used 100%, never less than 100%

[Robin_Guo]

@colings86

this output. No GC has happened during this output (since YGC and FGC have not increased) so I would not expect S1 to change. The eden space (E) is increasing and close to being full so I would expect a young GC to happen soon after the end of this output at which point I would expect S1 to drop to 0 (as any surviving object will be moved to S0) and S0 to increase to some value between 0 and 100 depending on the survival rate of the objects in the Eden space.

hi @colings86,

I've been monitoring the GC for a while, even if the YGC changed , but S1 never changed , it always 100, I never ever see the s1 changed to some valule.

171212105051 root@esdata02 ~ # jstat -gcutil 28948 2000 100
  S0     S1     E      O      M     CCS    YGC     YGCT    FGC    FGCT     GCT
  0.00 100.00  75.41  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  76.08  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  76.17  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  76.27  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  76.56  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  76.65  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  77.03  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  77.22  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  77.32  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  77.89  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  78.09  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  78.18  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  78.47  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  78.56  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  78.85  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  79.04  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  79.23  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  79.52  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  79.71  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  79.90  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  80.00  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  80.00  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  80.29  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  80.67  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  82.58  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  84.02  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  84.50  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  84.78  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  85.17  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  87.94  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  88.42  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  89.00  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  89.28  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  93.30  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00  94.93  82.10  91.54  82.89   2191  229.038     0    0.000  229.038
  0.00 100.00   8.53  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  12.40  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  13.95  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  15.50  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  21.71  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  28.68  55.35  91.54  82.89   2192  229.149     0    0.000  229.149
  0.00 100.00  29.46  55.35  91.54  82.89   2192  229.149     0    0.000  229.149