dummynet dropping too many packets

[rihad]

rihad wrote:
> For now we've mostly disabled dummynet and the drops have stopped, 
> thanks to some extra unused bandwidth we have. But this isn't a real 
> solution, of course, so this weekend I'm going to try the suggestion 
> made by Robert Watson:
> 
>  > In the driver init code in if_bce, the following code appears:
>  >
>  >         ifp->if_snd.ifq_drv_maxlen = USABLE_TX_BD;
>  >         IFQ_SET_MAXLEN(&ifp->if_snd, ifp->if_snd.ifq_drv_maxlen);
>  >         IFQ_SET_READY(&ifp->if_snd);
>  >
>  > Which evaluates to a architecture-specific value due to varying 
> pagesize.  You might just try forcing it to 1024.

> In a few days I'm going to try it anyway, and if the system locks up
> I'll just revert back to the original code >
> TIA
> 

Just rebooted with the "ifp->if_snd.ifq_drv_maxlen = 1024;" kernel, all 
ok so far. There's currenlty only 1000 or so entries in the ipfw table 
and around 350-400 net mbps load, so I'll wait a few hours for the 
numbers to grow to >2000 and 460-480 respectively and see if the drops 
still occur.

P.S.: BTW, there's a small admin-type inconsistency in FreeBSD 7.1: 
/etc/rc.firewall gets executed before values set by /etc/sysctl.conf are 
in effect, so "queue 2000" isn't allowed in ipfw pipe rules (as 
net.inet.ip.dummynet.pipe_slot_limit is only 100 by default), so the 
rules are silently failing without any trace in the log files - I only 
saw the errors at the console.