Comment 9 for bug 130075

iperf -c machine1 -d doesn't lock mine up, but adding "-p 2" (any
number of multiple threads) will do it every time, although not
necessarily right away.

And yes, this makes the forcedeth driver virtually useless on a
gigabit network. My findings were the same, only a reboot will bring
the interface back online.

db

On 9/25/07, BullCreek <email address hidden> wrote:
> I've played around with it a bit more, and even with the options
> max_interrupt_work=20 set in /etc/modprobe.d/forcedeth, it still
> happens. Only additional thing to report, is I happened upon an easy
> way to reproduce the hangup every time:
>
> 1. Login to machine1 which has a gigabit ethernet card in it and is
> attached to a gigabit switch. Run "iperf -s"
>
> 2. Login to a machine that has the gigabit forcedeth adapter in it -
> also hooked up to a gigabit switch. Run "iperf -c machine1 -d".
>
> The command in step two generates a lot of traffic in that it tells it
> to test speeds going both ways at once. On both my forcedeth systems,
> it will lock up the interface almost immediately, requiring a full
> reboot (i.e. /etc/init.d/networking restart has no effect). Note the
> problem only occurs under heavy load - if you just run iperf -c machine1
> without the -d option, it usually won't lock up.
>
> Should we report this bug to the kernel mailing list? I see that back
> in August, someone reported similar behavior in 2.6.22.1 but said adding
> the forcedeth.max_interrupt_work=20 option to their bootline fixed it
> (FWIW, I tried that and just go invalid option with feisty). Here is
> the thread:
>
> http://lkml.org/lkml/2007/8/5/92
>
> Does anyone know how to tell if the options in modprobe.d are in effect
> - dmesg doesn't show anything and lsmod doesn't have any flags? I have
> tried putting the appropriate line in /boot/grub/menu.lst, in
> /etc/modprobe.d/options, and in /etc/modprobe.d/forcedeth and as best as
> I can tell none have had any effect.
>
> P.S. I'm now wishing I had spent a little more and bought Intel boards
> with Intel NICs.
>
> --
> Random pauses when transferring data at gigabit speeds with forcedeth driver
> https://bugs.launchpad.net/bugs/130075
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