On the trail of a dummynet/bridge/ipfw bug.

[Darcy Buskermolen]

On Friday 14 March 2008 00:47:18 AT Matik wrote:
> On Thursday 13 March 2008 18:06:40 Wade Klaver wrote:
> > OK, here's something weird then.  ipfw pipe show | wc -l has reported
> > higher numbers:
> > [root at ibm3550b ~]# ipfw pipe show | wc -l
> >     3453
> > This was reported after the bridge "died" attempting 2600 simultaneous
> > connections... it had been running at 2400 before I added 200 more.
> > Now, immediately after the above crash, I do a /etc/rc.d/netif restart,
> > and then:
> > [root at ibm3550b ~]# ipfw pipe show | wc -l
> >     3900
> > Then as long as I add additional connections very slowly, I can manage
> > to get more established until it dies at 2800 with:
> > [root at ibm3550b ~]# ipfw pipe show | wc -l
> >     4160
> > At this point I am only using these numbers as a general indication of
> > pipe activity as the output is not 1 pipe per line.  In fact there is
> > more often than not two lines per pipe.  However, the end problem
> > remains the same.  After a point, the bridge doesn't get saturated, it
> > crashes and requires that the network be restarted before continuing.
> > The fact that it is necessary only to restart the network and not to
> > flush ipfw's pipes (which has no effect without a network restart)
> > perhaps suggests the problem lies in a different subsystem?  The
> > broadcom driver perhaps?

Wade, are you in a position to try this with a pair of intel gigE cards, using 
the em driver?  That should at least answer if it's a bce issue.


>
> hard to say because you do not tell so very much about your machine, it
> might be too weak for so many pipes (mem or cpu?),

The original post had the system configuration in terms of system, CPU and 
memory.

> I do not know your setup 
> or the nics you use
> you say it crash but can restart the network? probably you have some error
> in your script or since you run bridge some mac issue?