DragonFly BSD
DragonFly kernel List (threaded) for 2005-10
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Re: ftp runs slower on CPU 1

From: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>
Date: Mon, 24 Oct 2005 13:09:24 -0700 (PDT)

:Hi all,
:I am running a performance test on a dual cpu machine, with DragonFly
:1.3.7-DEVELOPMENT #2.
:The machine runs as ftp server.
:When ever the tcp thread runs on CPU0, the speed of the transfer is
:If the tcpu thread runs on CPU1, the speed is down to less than 40MB/sec.
:The detail of the setup and test is attached.
:Is is a problem?
:Thanks for your idea.

    I think the main issue is Big Giant Lock contention, and that isn't
    going to go away until we get it out of the network path.  We 
    are making progress in that department.  The light weight process
    work going into the tree will provide us with a good framework to
    start to remove it from the syscall path, and the interface queueing
    code, spin lock, and interrupt serializer APIs give us a good framework
    for removing it from the interrupt path.  The interrupt registration
    code now accepts the INTR_MPSAFE flag... so, really, we are making
    progress with the big picture even if it doesn't seem that way.


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