[Oisf-users] [Oisf-devel] [RFC] af-packet fanout configuration

chetan loke loke.chetan at gmail.com
Mon Aug 15 14:20:52 UTC 2011

On Mon, Aug 8, 2011 at 11:58 AM, Eric Leblond <eric at regit.org> wrote:
> Hello,
> I'm currently working on af-packet support following the  patches
> proposed by David Miller to support multiple threads reading on the same
> interface (similar to PF_RING cluster). Basic af-packet support is now
> working and I will now add support for this feature called fanout.

fanout in its current form may not work correctly for a mixed profile
data traffic. VLAN etc.
For a mixed-traffic you may end up overloading a single CPU, severely
hurting your performance.
Why fanout in user-space should also be looked at was discussed in
detail on the mailing list.
follow this thread -

Plus, some of the kernel paths are not plugged correctly. When you see
numbers on netdev for rfs/rps,
those are presented for a different use-case. IDS/packet-capture
appliance have different requirements.

Hope this helps.

> BR,
> --
> Eric Leblond

Chetan Loke

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