Should we keep the advice to increase queue max length?

[Duncan Roe <duncan_roe@optusnet.com.au>]

Hi Everyone,

Under the title "Performance", libnetfilter_queue main page advises

> increase queue max length with nfq_set_queue_maxlen() to resist to packets burst

but from experimenting it seems to me this does no good at all.

/proc/net/netfilter/nfnetlink_queue has a line for every active queue. The 3rd
field is the number of queued packets. The max length is not in these lines but
kernel source suggests it is 1024 by default. Anyway, I updated nfq6 to be able
to set the max (using mnl functions).

And I found the maximum number of queued packets is: 238. Further packets are
dropped.

If I lower the max below 238, limiting occurs at the new max.

So I propose to drop the advice to increase the queue max length when I revise
the libnetfilter_queue main page as part of the project to stop using
libnfnetlink.

Anyone have any comments?

Cheers ... Duncan.