FreeBSD 4.9 losing mbufs!!!

[Stephen Clark]

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 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
>
>  
>
I have discovered that if I disable quaqqa/ospfd then I don't lose 
mbufs! This makes it appear
that the mbuf leak is in the multicast routing logic. In fact I lose 
mbufs even with the both system basically idle but with a 100 vpn/gre 
with multicast going on thru the gre then the vpn.

Any ideas on where to focus my continued investigation?

Thanks to everybody who has responded.

Steve

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