Some performance measurements on the FreeBSD network stack

K. Macy kmacy at
Thu Apr 19 20:34:47 UTC 2012

>> 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 ?

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.


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