Re: Performance Intel Pro 1000 MT (PWLA8490MT)

From: Bosko Milekic (bmilekic_at_technokratis.com)
Date: 04/19/05

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    Date: Tue, 19 Apr 2005 17:42:09 -0400
To: Eivind Hestnes <eivind@stabbursmoen.no>

    On Tue, Apr 19, 2005 at 11:04:10PM +0200, Eivind Hestnes wrote:
    > It's correct that the card is plugged into a 32-bit 33 Mhz PCI slot. If
    > i'm not wrong, 33 Mhz PCI slots has a peak transfer rate of 133 MByte/s.
    > However, when pulling 180 mbit/s without the polling enabled the system
    > is very little responsive due to the interrupt load. I'll try to
    > increase the polling frequency too see if this increases the bandwidth
    > with polling enabled.. Thanks for the advice btw..
    >
    > - E.

       You are neglecting bus acquisition cycles as well as bus contention.
       Likely your 32-bit legacy PCI bus is shared between many devices.
       1Gbps for small packets is basically hopeless and you're probably
       stalling on the bus.

       Basically, a gigE card in a router you want to perform well in
       anything but a high-speed PCI-X bus (hopefully little or not
       contested) has been a terrible waste of money, in my experience.

    -Bosko

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