FreeBSD 4.9 losing mbufs!!!

Nikos Vassiliadis nvass at teledomenet.gr
Tue Apr 18 14:14:28 UTC 2006


On Tuesday 18 April 2006 16:50, Stephen Clark wrote:
> Hello List,
>
> I know 4.9 is ancient history, but unfortunately we have several
> thousand sites installed. We are in the process of moving to 6.1 when it
> is released.
>
> Right now I have an immediate problem where we are going to install two
> system

so these are new systems, yet you are going to use 4.9.
Why?

>  at a HQ site. Each of the 2 systems will have two gre/vpn/ospf tunnels to a
> 100 remote sites in the
> field. The broadband will be a T3 with failover to dialup actiontec
> dualpc modems. We want
> to use FreeBSD systems rather than put in Cisco equip which is what we
> have done for other
> large customers.
>
> The problem:
>
> I have been testing between an Athlon 64 3000+ (client)  and an Athlon
> 64 X2 4800+ (server) across a dedicated 100mb lan. When I use nttcp,
> which is a round trip tcp test, across the gre/vpn the client system,
> (which goes to 0 percent idle), network stack will eventually stop
> responding. In trying to track this down I find that
> net.inet.ip.intr_queue_maxlen which is normally 50 has been reached (I
> added a sysctl to be able to look at it), but it never drains down. If I
> increase it things start working again. If I continue to hammer the
> client I see the
> intr_queue_maxlen continue to grow until it again reaches the new
> maximum. Another datapoint if I don't send the data thru the gre tunnel,
> but only thru the vpn I don't see this problem.
>
> I've looked at the gre code til I am blue in the face and can't see
> where mbufs  were not being freed when the quelen is full.
>
> If anybody could give some direction as where to look or how to better
> trouble shoot this problem it would be greatly appreciated.
>
> Thanks for being such a great list,
> Steve


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