javagarbage-collectionjvmjstat

No swap in survivor area


jstat -gc This is the result of my gc command. Why is the survivor area not swapped after Minor GC? Why didn't the old age increase at all?


Solution

  • S0C/S0U counters are not used with G1 GC.

    G1 has no dedicated survivor spaces and no dedicated old/young areas. Any G1 region can serve as Old, Young or Survivor. See this article for details.

    S1C/S1U jstat counters represent the total amount of memory occupied by survivor regions; S0C/S0U are always zero.