Re: Some performance measurements on the FreeBSD network stack

On Thu, Apr 19, 2012 at 10:34:45PM +0200, K. Macy wrote:
> >> This is indeed a big problem. ?I'm working (rough edges remain) on
> >> changing the routing table locking to an rmlock (read-mostly) which
> >
> 
> This only helps if your flows aren't hitting the same rtentry.
> Otherwise you still convoy on the lock for the rtentry itself to
> increment and decrement the rtentry's reference count.
> 
> > i was wondering, is there a way (and/or any advantage) to use the
> > fastforward code to look up the route for locally sourced packets ?

actually, now that i look at the code, both ip_output() and
the ip_fastforward code use the same in_rtalloc_ign(...)

> >
> 
> If the number of peers is bounded then you can use the flowtable. Max
> PPS is much higher bypassing routing lookup. However, it doesn't scale
> to arbitrary flow numbers.

re. flowtable, could you point me to what i should do instead of
calling in_rtalloc_ign() ?

cheers
luigi