Re: intel 82599 multi-port performance

On 09/26/2011 10:46 AM, Chris Friesen wrote:

On 09/26/2011 11:24 AM, Ben Greear wrote:

quoted

On 09/26/2011 09:40 AM, Chris Friesen wrote:

quoted

quoted

To any of the Intel guys out there...any ideas? Can an 82599 on an 8x
bus handle max line rate with minimum size packets?

Rick Jones sent me an interesting link related to this. Short answer seems
to be 'yes', but it seems not for any normal off-the-shelf software stack.

quoted

This: http://comments.gmane.org/gmane.linux.network/203602 should

lead you to some slide.

Interesting. I wonder if Intel's DPDK will be the only way to handle those sorts of packet rates.

Pktgen is probably still the fastest general code that I know of,
but we had some interesting results setting the TCP_MAXSEGS to
88, which creates around 150 byte packets, and let the NICs offload
chop up large TCP writes into small packets on the wire.

Using core-I7 980x CPU, and dual-port 82599, we could send
around 4Mpps and receive around 2Mpps between two machines.
We were using a single port on each NIC/machine for this test.  Connection
was a bit asymmetric, seems one side would over-power the other...so if
we twiddled a bit, we could get around 3Mpps in each direction.

Our user-space app has some over-head as well, but we can send
at least 5Gbps full duplex on two ports using normal sized frames, so I
think the bottleneck in this case is the TCP offload in the NIC.

Still, pretty impressive for stateful TCP packets per second :)

Top-of-tree netperf just learned to do the TCP_MAXSEG trick as well,
so it might be fun to play with that.  It probably has less overhead
than our tool, so might run even faster.

Thanks,
Ben

-- 
Ben Greear [off-list ref]
Candela Technologies Inc  http://www.candelatech.com


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