lkml.org 
[lkml]   [2000]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: Gigabit Linux Server Bottlenecks
    From
    Date
    >>>>> "Ingo" == Ingo Molnar <mingo@chiara.csoma.elte.hu> writes:

    Ingo> On Tue, 8 Feb 2000, Anton Ivanov wrote:

    >> Wrong. All GigE cards I have checked so far have interrupt
    >> mitigation. At init you program them to delay IRQ until that many
    >> packets are in the queue or a timer expires and the timer
    >> value. The only problem is that these are usually not passed as
    >> module params. So you have to recompile if you find your current
    >> mitigation params bad.

    Ingo> yep, also with jumbo frames (mtu 9000) there is no problem at
    Ingo> all. Eg. the SysKonnect cards i use do just over 20k IRQs/sec
    Ingo> when i'm saturating 107MB/sec TCP bandwith - this IRQ load is
    Ingo> simply not a problem at all for an APIC controller. I've seen
    Ingo> IRQ rates of 80k/sec as well.

    Sorry but thats *BAD* performance by the SK card. I do around 2.5K
    ints/sec with the Alteon when doing 65MB/sec traffic in one direction
    with regular sized frames. The load is maybe not a problem for the
    APIC, but 80k/sec truly sucks for the CPUs considering the number of
    context saves/restores they have to do.

    >> See above. If you program a sane GigE NIC correctly you actually
    >> transfer more than 8K at a time. Donald Becker's hamachi driver is
    >> a good example.

    Ingo> also other cards are using jumbo frames as well (and it actually
    Ingo> makes sense to increase packet size).

    It's the switch vendors who are causing the problems.

    Jes

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.rutgers.edu
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:56    [W:2.815 / U:0.264 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site