Kernel timers are inaccurate some times

Solution Verified - Updated -


  • We notice that there's an important and varying delay (eg. up to 4 minutes) between the expiration of the linux kernel net.ipv4.tcp_keepalive_time timer (3600 secs) and the actual sending of the tcp_keepalive (ack) packets, leading to unwanted aging of idle sessions by our firewall.
    • The higher the net.ipv4.tcp_keepalive_time value the longer the delay.
  • Other kernel timers not just network timers like delayed work timers and possibly storage are also affected.


  • Red Hat Enterprise Linux 8.3
  • other kernel timers
  • TCP keepalive
  • TIME WAIT timers

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