Re: Steep drop in throughput using NFQUEUE

[Rick Jones <rick.jones2@hp.com>]

On 11/22/2011 11:35 AM, Hariharan Thantry wrote:
> Hi folks,
>
> I'm trying to setup an IPS infrastructure using Suricata. My setup is
> the following:
>
> Machine A (Client): Regular Desktop with one dual ported 10G 82599 NICs
> Machine B (Bridge, hosting Suricata): An entry level Xeon with 2 dual
> ported 10G 82599 NICs
> http://www.newegg.com/Product/Product.aspx?Item=N82E16813131725
> Machine C (Server): Regular Desktop with one dual ported 10G 82599 NIC
>
> Note that the machine hosting Suricata is a ___pure___ bridge (no IP address)
>
> The forwarding performance of the bridge with the single 10G
> connection active is ~9.5 Gbps (almost line rate), while with both 10G
> connections active is ~ 13 Gbps (no tuning).

Doesn't help with the NFQUEUE bit, but ~13 Gbps sounds like what someone 
recently asserted was an expected practical limit for a dual-port NIC in 
a x4 Gen2 slot.

For the NFQUEUE vs other bit, sounds like some profiling is in order.

rick jones

>
> While trying out Suricata as an IPS in this setup, I noticed a steep
> drop in the forwarding rate. The single 10G connection speeds dropped
> to ~ 400 Kbps.
>
> The Suricata machine has the following rule setup:
>
> $ sudo iptables -A FORWARD -j NFQUEUE --queue-num 0
>
> To see if the drop in the rate was independent of the Suricata stack
> or not, I ran the example program from here:
>
> http://www.netfilter.org/projects/libnetfilter_queue/doxygen/nfqnl__test_8c_source.html
>
> and noticed that the speeds are the same as above (~400 Kbps). With
> COPY_META, the speeds increased to ~ 2Mbps.
>
> Is this steep drop expected? Any suggestions on what I could be
> missing, or how could I optimize it?
>
> Interestingly, using ebtables, and its user space handler
>
> $sudo ebtables -A FORWARD --ulog-nlgroup 1
> http://ebtables.sourceforge.net/examples/basic.html#ex_ulog
> kept up with the line rate, which was rather surprising, because even
> that handler involves a copy to user space.
>
> Any suggestions would be appreciated.
>
> Thanks,
> Hari
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