Re: NetBSD/xen network problems (need help)

["Mike M. Volokhov" <mishka%intostroy.com@localhost>]

On Mon, 23 Jan 2006 12:41:54 +0100
Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:

> On Mon, Jan 23, 2006 at 10:34:01AM +0200, Mike M. Volokhov wrote:
[snip]
> >   4650 packets transmitted, 2949 packets received, +27752 duplicates, 36.6% 
> > packet loss
> >   round-trip min/avg/max/stddev = 16.536/43066.884/94286.876/29929.792 ms
> 
> From where to where is this ping ? Also  it would be interesting
> to run tcpdump on the other end, to see in which direction the
> packet is dupliced.

The path is as follows:

[LAN host] --- [xvif2.0] --- [xvif2.1] --- [host in the Internet]

[snip]
> Lots of errors on xvifs. Do you have any message in dmesg ? In the
> driver, there are several places where there is a printf before the input
> error counter is incremented.
> However, one place where it's silently incremented is if it can't get
> a mbuf (e.g. if you get "mclpool limit reached"). This would also explain
> the network hangs.

Any. Not in dom0, nor domUs.

> > Name  Mtu   Network       Address              Ipkts Ierrs    Opkts Oerrs 
> > Colls
> > lo0   33192 <Link>                                28     0       28     0   
> >   0
> > xenne 1500  <Link>        aa:00:00:04:e7:86   179545     0   111152 88327   
> >   0
> 
> The output errors on this side are probably related to the input errors
> on the dom0.

This may be beacuse of xennet/bridge tandem. ``The problem occurs when a
new (unlearnt) mac address is seen by bridge which passes to all
if_xennetS. Then all those doms send the packet back to the bridge ttl
- 1 using their src mac, which presumably the bridge learns then.'' See
also private mail from me.

> > Also, I've faced with kernel panics on domU machine (see below; btw,
> > how to save core dump? "sync" isn't working - dump device bad, /netbsd
> > is a copy of really booted kernel).
> 
> kernel core dump don't work yet on Xen, It's on my todo list.

Will know, thanks for explaination...

--
Mishka.