Linux shaping packet loss

Chris chris at ghostbusters.co.uk
Thu Dec 10 06:49:33 CST 2009


Thanks to all that replied.

Trial and error it is ... I'm now waiting (22 hours later) for it to break
again after I changed the priority on the "default" catch-all class. It
lasted five days before.

I'm looking at CBQ but it's not at all friendly relative to HTB.

If I'm forced to go down the proprietary traffic-shaping route. What's good
for really cheap gigabit, redundant, high throughput (including during
64-byte UDP attacks) shapers ? Suggestions appreciated.

Chris

2009/12/9 Nickola Kolev <nikky at mnet.bg>

> На Wed, 09 Dec 2009 06:38:31 +0000
> gordon b slater <gordslater at ieee.org> написа:
>
> > On Wed, 2009-12-09 at 08:02 +0200, Bazy wrote:
> >
> > > Hi Chris,
> > >
> > > Try setting txqueuelen to 1000 on the interfaces and see if you
> > > still get a lot of packet loss.
> > >
> >
> > Yes, good point and well worth a try. Rereading Chris's post about
> > "250Mbps" and "forty queues", the "egress" could well be bumping the
> > end of a default fifo line.
> >
> > If 1000 is too high for your kit try pushing it upwards gradually from
> > the default of 100 (?) but back off if you get drops or strangeness in
> > ifconfig output on the egress i/f.
>
> The default *is* 1000. From the ifconfig man page:
>
> txqueuelen length
>
> Set  the  length  of the transmit queue of the device. It is useful to
> set this to small values for slower devices with a high atency (modem
> links, ISDN) to prevent fast bulk transfers from disturbing interactive
> traffic like telnet too much.
>
> So, if you should touch it if and only if you want to have (supposedly)
> finer grained control on queueing, as the hardware device also does
> some reordering before it puts the data on the wire.
>
> > I append grep-ped ifconfig outputs into a file every hour on a cron
> > job until I'm happy that strangeness doesn't happen, they never do
> > when you're watching sadly.
> >
> > TC problems aren't always about the TC itself, the physical interfaces
> > are inherently part of the "system", as my long rambling 5am+
> > up-all-night-over-ssh post about reseating NICs was trying to hint
> > at.
> >
> > Nice one Bazy
> >
> > Gord
> >
> >
> >
> >
> >
>
>
> --
> Regards,
> Nickola
>
>



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