High ping latency correlation with high server activity - TCP-IP

This is a discussion on High ping latency correlation with high server activity - TCP-IP ; Hello, I got a situation that some servers in our network (connected with giga switch) have sometimes high latency peaks more than 10ms that usually at or =1 ms latency. those servers are intensive memory,cpu,disk ,network about 30 to 40 ...

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Thread: High ping latency correlation with high server activity

  1. High ping latency correlation with high server activity

    Hello,
    I got a situation that some servers in our network (connected with
    giga
    switch) have sometimes high latency peaks more than 10ms that usually
    at <1
    or =1 ms latency.
    those servers are intensive memory,cpu,disk ,network about 30 to 40 %
    average usage.
    my question ,is there any correlation with those component to the fact
    that
    network monitoring shows sometimes high latency?.
    Thanks

  2. Re: High ping latency correlation with high server activity

    On 2008-04-29 08:25:50 -0400, tbaror@gmail.com said:

    > Hello,
    > I got a situation that some servers in our network (connected with
    > giga
    > switch) have sometimes high latency peaks more than 10ms that usually
    > at <1
    > or =1 ms latency.
    > those servers are intensive memory,cpu,disk ,network about 30 to 40 %
    > average usage.
    > my question ,is there any correlation with those component to the fact
    > that
    > network monitoring shows sometimes high latency?.
    > Thanks



    Interesting observation, and I've observed the same - my conclusion
    after some analysis and testing is that returning ICMP echo reply
    packets has the lowest priority in the kernel of some (maybe most?)
    operating systems, this is also true of a lot of commercial routing
    gear, etc. Certainly not the only answer / however, it could also be
    that your ICMP echo / reply traffic is seeing latency co-mingled with
    other traffic being generated when the server is busy.

    /dmfh

    --
    _ __ _
    __| |_ __ / _| |_ 01100100 01101101
    / _` | ' \| _| ' \ 01100110 01101000
    \__,_|_|_|_|_| |_||_| dmfh(-2)dmfh.cx


  3. Re: High ping latency correlation with high server activity

    On Apr 29, 5:25 am, tba...@gmail.com wrote:

    > I got a situation that some servers in our network (connected with
    > giga
    > switch) have sometimes high latency peaks more than 10ms
    > that usually
    > at <1
    > or =1 ms latency.
    > those servers are intensive memory,cpu,disk ,network about
    > 30 to 40 %
    > average usage.
    > my question ,is there any correlation with those component to the
    > fact that
    > network monitoring shows sometimes high latency?.


    How are you measuring latency? If you're measuring with 'ping', it's
    probably the time to get through the queues on the network card. If
    you're measuring in an application, it's probably the time to schedule
    the application and switch to it.

    Depending on the OS, configuration, and load profile, it may help to
    adjust the scheduler interval.

    DS

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