Firewall Profiling.

[Juli Mallett]

2011/12/27 Lev Serebryakov <lev at freebsd.org>:
> Hello, Luigi.
> You wrote 27 декабря 2011 г., 18:26:00:
>
>> plans, yes - not sure how long it will take. I have compiled
>> ipfw+dummynet as a standalone module (outside the kernel)
>> but have not yet hooked the code to netmap to figure out how fast
>> it can run.
>  I still don't understand why it should be faster than "normal" way,
> as it is essentially same (ipfw + dummynet) code + some additional
> context switches for netmap (to userland and back).
>  What does netmap shave off from packet processing in this particular
> case, to compensate context switches? I

Reloading of mbufs into DMA descriptors?  mbuf allocator overhead
itself?  Interrupts.  Context switches under constant heavy load.
Some indirection in the network stack.