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    SubjectRe: [RESEND] tuning linux for high network performance?
    On Wed, 23 Oct 2002, bert hubert wrote:

    > On Wed, Oct 23, 2002 at 03:42:48PM +0200, Roy Sigurd Karlsbakk wrote:
    > > > The e1000 can very well do hardware checksumming on transmit.
    > > >
    > > > The missing piece of the puzzle is that his application is not
    > > > using sendfile(), without which no transmit checksum offload
    > > > can take place.
    > >
    > > As far as I've understood, sendfile() won't do much good with large files. Is
    > > this right?
    >
    > I still refuse to believe that a 1.8GHz Pentium4 can only checksum
    > 250megabits/second. MD Raid5 does better and they probably don't use a
    > checksum as braindead as that used by TCP.
    >
    > If the checksumming is not the problem, the copying is, which would be a
    > weakness of your hardware. The function profiled does both the copying and
    > the checksumming.
    >
    > But 250megabits/second also seems low.
    >
    > Dave?
    >

    Ordinary DUAL Pentium 400 MHz machine does this...


    Calculating CPU speed...done
    Testing checksum speed...done
    Testing RAM copy...done
    Testing I/O port speed...done

    CPU Clock = 400 MHz
    checksum speed = 685 Mb/s
    RAM copy = 1549 Mb/s
    I/O port speed = 654 kb/s


    This is 685 megaBYTES per second.

    checksum speed = 685 Mb/s



    Cheers,
    Dick Johnson
    Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
    Bush : The Fourth Reich of America


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