Making IFQ_MAXLEN tunable

Julian Elischer julian at
Fri Apr 30 21:33:45 UTC 2010

On 4/30/10 1:23 PM, Maxim Sobolev wrote:
> Hi,
> Many network drivers in the FreeBSD kernel use the IFQ_MAXLEN value to
> set length of the outgoing packets queue. The default value for that
> parameter is only 50, which is pretty low especially for the cases when
> the system handles lot of small packets and can cause ENOBUFS in
> applications under the load. The following patch makes IFQ_MAXLEN a
> tunable. I am also tempted to bump the default value for IFQ_MAXLEN
> 10-fold, but would like to hear what do people think about it first.
> -Maxim
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so just tunable? not a sysctl :-)

patch could be a lot smaller if you defined IFQ_MAXLEN to be 
V_ifqmaxlen (do different vimages want a different value?)

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