JVM GC 次数没有这么时间突然增加

Question

使用 jstat -gcutil 监控程序 gc 情况时，为何突然之间有一跳时间增加了而 YGC 和 FGC 都没有增加。

 S0     S1     E      O      M     CCS    YGC     YGCT    FGC    FGCT     GCT
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
 40.57   0.00   0.00  96.12  94.08  91.92    254   59.554     3    0.137   59.691
  0.00   0.00   5.90  75.31  93.06  89.80    254   59.554     3   66.918  126.472
  0.00   0.00  17.40  75.31  93.06  89.80    254   59.554     3   66.918  126.472
  0.00   0.00  28.79  75.31  93.06  89.80    254   59.554     3   66.918  126.472
  0.00   0.00  40.57  75.31  93.06  89.80    254   59.554     3   66.918  126.472
  0.00   0.00  50.96  75.31  93.06  89.80    254   59.554     3   66.918  126.472
  0.00   0.00  62.64  75.31  93.06  89.80    254   59.554     3   66.918  126.472