TCP/Ip sockets slowdown - IBM AS400

This is a discussion on TCP/Ip sockets slowdown - IBM AS400 ; We have a data transfer program using c sockets on te iSeries. It seems like the data transfer is slowing down running on 1gbt ethernet, as the transfer proceeds. FTP on the same iseries/pc combo runs fine with no slowdown. ...

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Thread: TCP/Ip sockets slowdown

  1. TCP/Ip sockets slowdown

    We have a data transfer program using c sockets on te iSeries. It
    seems like the data transfer is slowing down running on 1gbt ethernet,
    as the transfer proceeds. FTP on the same iseries/pc combo runs fine
    with no slowdown.

    We made a sample program to just send data blocks without even reading
    a file, and it slows down also.

    The slowdown seems to happen on several iSeries servers we have tested
    this on. We can't tell if the tcp/ip itself is being throttled down,
    or perhaps the job is dynamically receiving lower priority because it
    seems to be io bound.

    If anyone has na ideas on this, I would appreciate it. I've googled
    searched and read the ibm tcp/ip manual, but haven't found a hint of
    this.


  2. Re: TCP/Ip sockets slowdown

    Hi Brad

    I'd start with a system monitor in Management central, check the CPU,
    Disk I/O, LAN I/O stats and check to see if the job priority is
    changing and work out what else the iSeries is doing as the job
    proceeds.

    If you can check the job log of the sockets program.

    Just one though, how are you running the Socket program, hopefully not
    interactively, if so you may find CFINT in hammering your job after a
    short while, this will show in the system monitor, may sure it's in
    batch.

    Good Luck Brad



  3. Re: TCP/Ip sockets slowdown

    Thanks for the suggestion,s it turns out I was wrong about the source
    of my problems.

    The slowdown was on the PC side. I converted my internal data handling
    to stop moving the data around, and switched to the dll version of the
    tcp/ip socket system. The result is my tapeless back for the as/400
    now runs 4 times as fast, and beats LTO tape, which was our design
    goal.

    Thanks for the good suggestions all the same.

    Brad Jensen
    www.laservaultbackup.com

    > Just one though, how are you running the Socket program, hopefully not
    > interactively, if so you may find CFINT in hammering your job after a
    > short while, this will show in the system monitor, may sure it's in
    > batch.
    >
    > Good Luck Brad




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