RE: Some performance measurements on the FreeBSD network stack

>
>From previous tests, the difference between flowtable and
>routing table was small with a single process (about 5% or 50ns
>in the total packet processing time, if i remember well),
>but there was a large gain with multiple concurrent processes.
>

Yes, that sounds about right when we did the tests a long while ago.

>
> Removing flowtable increases the cost in ip_output()
> (obviously) but also in ether_output() (because the
> route does not have a lle entry so you need to call
> arpresolve on each packet). 
>

Yup.

>
> So in revising the route lookup i believe it would be good
> if we could also get at once most of the info that
> ether_output() is computing again and again.
>

Well, the routing table no longer maintains any lle info, so there
isn't much to copy out the rtentry at the completion of route
lookup.

If I understood you correctly, you do believe there is a lot of value
in Flowtable caching concept, but you are not suggesting we reverting
back to having the routing table maintain L2 entries, are you ?

--Qing