Hello,

I just had the opportunity to test some Fluke network equipment, notably
one which is able to throughput test gigabit networks.

I installed a Nexcom NSA1086 with OpenBSD 4.1-stable and did some tests.
The NSA1086 units are equipped with a Pentium IV 3.2Ghz (hyperthreading
disabled), and 1Gb ram. They have 4 sk gigabit interfaces, and 4 msk
gigabit interfaces. Here are the tests:

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ifconfig sk0 up
ifconfig sk1 up
ifconfig bridge0 create
ifconfig bridge0 up
brconfig bridge0 add sk0
brconfig bridge0 add sk1
sysctl kern.maxclusters=256000

Then I connected the fluke analyzers to both sk ports. connections were
correctly seen at 1000 base T full Duplex. then I started a throughput
test on 1Gbps, and I was extremely surprised to see how performance was
very poor. The throughput was only about 77Mbps.

***************

Seeing that I decided to try on msk interfaces and got about the same
"performance".

***************

Then I configured routing between two interfaces.
ifconfig sk2 inet 192.168.0.1 255.255.255.0
ifconfig sk3 inet 192.168.1.1 255.255.255.0
sysctl net.inet.ip.forwarding=1
sysctl kern.maxclusters=256000

I did the throughput test, and got about 500Mbps both on sk and msk,
with the CPU keeping quiet.

**************

So the weak performance doesn't seem related to the bus, the CPU, or the
sk/msk drivers. Has someone an explanation on why I get this kind of
behavior?