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    SubjectRe: BUG: Slowdown on 3000 socket-machines tracked down
    Nick Piggin wrote:
    > Ben Greear wrote:
    >
    >> Christian Schmid wrote:
    >>
    >>> Ben Greear wrote:
    >
    >
    >>>> How many bytes are you sending with each call to write()/sendto()
    >>>> whatever?
    >>>
    >>>
    >>>
    >>> I am using sendfile-call every 100 ms per socket with the poll-api.
    >>> So basically around 40 kb per round.
    >>
    >>
    >>
    >> My application is single-threaded, uses non-blocking IO, and
    >> sends/rcvs from/to memory.
    >> It will be a good test of the TCP stack, but will not use the sendfile
    >> logic,
    >> nor will it touch the HD.
    >>
    >
    > I think you would have better luck in reproducing this problem if you
    > did the full sendfile thing.
    >
    > I think it is becoming disk bound due to page reclaim problems, which
    > is causing the slowdown.
    >
    > In that case, writing the network only test would help to confirm the
    > problem is not a networking one - so not useless by any means.

    It's not trivial to write something like this :)

    I'll be using something I already have. If I can't reproduce the problem,
    then perhaps it is due to sendfile and someone can write a customized
    test. The main reason I offered is because people are ignoring the
    bug report for the most part and asking for a test case. I may be able
    to offer an independent verification of the problem which might convince
    someone to write up a dedicated test case...

    Ben


    --
    Ben Greear <greearb@candelatech.com>
    Candela Technologies Inc http://www.candelatech.com

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