Igb driver - header split feature

[Rafael Ganascim]

Hi list,

I was looking in the igb driver that I use on some Intel nics
(dualport and quadport gigabit) and in the source code, the feature:

/*
** Header split causes the packet header to
** be dma'd to a seperate mbuf from the payload.
** this can have memory alignment benefits. But
** another plus is that small packets often fit
** into the header and thus use no cluster. Its
** a very workload dependent type feature.
*/

Somebody is using this feature? What's the results?

I think that this feature can be helpfull to improve the performance,
allowing the processing of the packet headers more fastest (pfills,
routing, etc). Is this true?

Thanks in advance.

Rafael