pcp-pmie outputs many logs when the system clock is changed to future date

Issue

• pcp-pmie outputs many logs when system clock is changed to future date.

  # date
  Thu Nov 23 21:23:34 JST 2023
  # date -s "2023-12-25 14:33:00"
  # less /var/log/messages
  ...omit...
  Dec 25 14:33:27 rhel8 pcp-pmie[121049]: High aggregate context switch rate 94423ctxsw/s@rhel8
  Dec 25 14:33:27 rhel8 pcp-pmie[121049]: High aggregate context switch rate 93877ctxsw/s@rhel8
  Dec 25 14:33:28 rhel8 pcp-pmie[121049]: High aggregate context switch rate 79504ctxsw/s@rhel8
  Dec 25 14:33:28 rhel8 pcp-pmie[121049]: High aggregate context switch rate 82977ctxsw/s@rhel8
  Dec 25 14:33:28 rhel8 pcp-pmie[121049]: Some CPU busy executing in system mode 939%sys[cpu4]@rhel8 939%sys[cpu11]@rhel8
  Dec 25 14:33:28 rhel8 pcp-pmie[121049]: High aggregate context switch rate 90462ctxsw/s@rhel8
  Dec 25 14:33:28 rhel8 pcp-pmie[121049]: Some CPU busy executing in system mode 842%sys[cpu12]@rhel8
  ...omit repeating...