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Re: high cpu load with tcpdump



On Mon, 29 Feb 2016, Christos Zoulas wrote:


This tcpdump ktrace is when bind is running, right?
What happens if you stop it? How does the ktrace look then?
Or once you start bind, tcpdump goes nuts and stays that way?

You're right. When tcpdump is started after the bind, tcpdump caused problems.


Here the ktrace (tcpdump before bind)

  3451      1 tcpdump  1456839639.234979724 RET   read 0
  3451      1 tcpdump  1456839639.234983565 CALL  read(3,0x7f7ff7b16000,0x80000)
  3451      1 tcpdump  1456839640.235319234 GIO   fd 3 read 0 bytes      ""
  3451      1 tcpdump  1456839640.235322516 RET   read 0
  3451      1 tcpdump  1456839640.235328872 CALL  read(3,0x7f7ff7b16000,0x80000)
  3451      1 tcpdump  1456839641.235662445 GIO   fd 3 read 0 bytes      ""
  3451      1 tcpdump  1456839641.235665868 RET   read 0
  3451      1 tcpdump  1456839641.235670128 CALL  read(3,0x7f7ff7b16000,0x80000)
  3451      1 tcpdump  1456839642.236012990 GIO   fd 3 read 0 bytes      ""
  3451      1 tcpdump  1456839642.236017460 RET   read 0
  3451      1 tcpdump  1456839642.236021371 CALL  read(3,0x7f7ff7b16000,0x80000)
  3451      1 tcpdump  1456839643.236348030 GIO   fd 3 read 0 bytes      ""


In this case all works fine. There is also no change in the bind ktrace.


Regards
Uwe



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