Freebsd IP Forwarding performance (question, and some info) [7-stable, current, em, smp]

Sepherosa Ziehau sepherosa at
Tue Jul 1 05:05:38 UTC 2008

On 7/1/08, Adrian Chadd <adrian at> wrote:
> 2008/7/1 Sepherosa Ziehau <sepherosa at>:
>  > Properly configured #RX desc and timer intr interval will be required
>  > to make sure that the RX desc collection could keep up with the
>  > hardware speed.  I used pure timer intr (8000Hz) on nfe(4) in dfly w/
>  > good result, i.e. TX/RX @linespeed without livelocking the system.
>  > The drawback of pure timer intr is that you waste extra cpu power,
>  > when there is nothing to process.
> What packet rate is "linespeed" ? With what size packets?

I did not mean pps w/ 64bytes packet.  Didn't have time to measure it
yet.  I only saw that msk(4) and em(4) could accept 64bytes packets
@1.4Mpps.  I meant netperf -t TCP_STREAM with -s/-S/-m 65536 on an
AMDX2 3600+ with 1GBytes ram in i386 mode.

Best Regards,

Live Free or Die

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