Kernel timers are inaccurate some times
Issue
- 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.
- The higher the
- Other kernel timers not just network timers like delayed work timers and possibly storage are also affected.
Environment
- Red Hat Enterprise Linux 8.3
- other kernel timers
- TCP keepalive
- TIME WAIT timers
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