Re: VLAN I/F's and TX queue.

[Eric Dumazet <eric.dumazet@gmail.com>]

Le lundi 10 mai 2010 à 16:54 +0200, Joakim Tjernlund a écrit :
> Patrick McHardy <kaber@trash.net> wrote on 2010/05/10 16:41:40:
> >
> > Eric Dumazet wrote:
> > > Le lundi 10 mai 2010 à 16:26 +0200, Patrick McHardy a écrit :
> > >
> > >> Is the intention just to avoid accounting the packet as dropped?
> > >> That seems fine to me since in case of NET_XMIT_CN its actually
> > >> not the currently transmitted packet that was dropped.
> > >>
> > >> But part of the intention of the above mentioned patch was actually
> > >> to inform higher layers of congestion so they can take action if
> > >> desired, which would be defeated by this patch.
> > >>
> > >
> > > I see, so maybe we want following patch instead ?
> > >
> > > (letting NET_XMIT_CN be given to caller, but accounting current packet
> > > as transmitted ?)
> >
> > Perfect, thanks. I'd suggest to change macvlan in a similar fashion
> > for consistency though.
> >
> > In any case please feel free to add my
> >
> > Acked-by: Patrick McHardy <kaber@trash.net>
> 
> hmm, as I don't follow this could you tell me where the dropped pkgs
> are accounted in my case:
>  eth0      Link encap:Ethernet  HWaddr 00:AA:BB:CC:DD:EE
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:8886910 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:8880219 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:100
>            RX bytes:1626842951 (1.5 GiB)  TX bytes:1555540810 (1.4 GiB)
> 
>  eth0.1    Link encap:Ethernet  HWaddr 00:AA:BB:CC:DD:EE
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:2163164 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:2161943 errors:0 dropped:98 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:2467090557 (2.2 GiB)  TX bytes:2480246455 (2.3 GiB)
> 
>  eth0.1.1  Link encap:Ethernet  HWaddr 00:AA:BB:CC:DD:EE
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:2163164 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:2161943 errors:0 dropped:98 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:2458437901 (2.2 GiB)  TX bytes:2471598683 (2.3 GiB)
> 
> -

As I already said to you, this is a side effect, because your eth0.1.1
and eth0.1 have no queue.

Packet is not dropped, its only a congestion indication.

If you use a queue on eth0.1.1, queue itself handle the queueing
(obviously), and queue drops are not reported in 'ifconfig -a', but in 
'tc -s -d qdisc'