Re: [HEADS UP!] IPFW Ideas: possible SoC 2008 candidate

Robert Watson wrote:

On Tue, 25 Mar 2008, Sepherosa Ziehau wrote:

On Tue, Mar 25, 2008 at 1:53 AM, Julian Elischer <julian@xxxxxxxxxxxx> wrote:

3/ possibly keeping per CPU stats..


This probably is the trickest part, not difficult for non-fastforward case. But if fastforward is enabled, I could only imagine full cross-cpu states duplication.


FWIW, there is decreasing difference between IP fast forwarding and regular IP processing in FreeBSD 7.x, as we perform direct dispatch by default, so it's not just the fast forward case where full input parallelism is possible for the firewall, and parallel firewall processing has occurred for output since 5.3.

The regular forwarding path still does a (partial) copy of each packet
it forwards. This is done for the ICMP redirect functionality. Additionally
it has a much larger I-cache footprint due to the full ip_input(), ip_forward()
and ip_output() functions being executed. Yes, the delta is shrinking but
still quite big. I think regular forwarding still hits the wall at around
300-350kpps whereas fastforward can do 500kpps up to 1mpps with a good hardware
base.

--
Andre

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