OpenBSD Journal

OpenBSD 4.9 Latency and Throughput testing

Contributed by pitrh on from the filling-the-tubes dept.

Andrew Fresh wrote in to tell us about his recent work in measuring key performance data for OpenBSD 4.9 using professional-grade testing equipment. Andrew writes,

“

I have been working to build a new router for a customer and have had access to a pair of Spirent SmartBits SMB-600 with gigabit interfaces. This gave me the opportunity to do some testing. The machines available are Dell PowerEdge 860's with "80557,Xeon 3000 Conroe,3060,LGA775,Burn 2" processors. I tested with the onboard bge interfaces and thanks to Dave some em NICs as well.

The testing shows that with a single processor kernel for any average packet size above 767 bytes you can easily saturate a gigabit network interface forwarding packets. I was able to achieve close to 300k pps in any configuration I tested. Surprisingly with small packet sizes, amd64 did slightly better than i386 achieving a maximum of of 347,812 pps with an em NIC. Until the interface was saturated, latency remained low at less than 500 microseconds.

”

For more details and pictures, see the full post.

(Comments are closed)

Comments

  1. By Dan Shechter (danshtr) danshtr@gmail.com on

    If I understand correctly, you made PF run on its rule set for each and every packet going through. Which makes the results very impressive!

    I wonder what would have happened if you tried UDP and not TCP, and jeep the state.

    Comments

    1. By Andrew Fresh (andrew) on http://www.afresh1.com

      The program I was using to generate the packets does not support creating actual tcp flows, for that I would need a more advanced piece of software to control the testing hardware. The simple one is complicated enough for the amount of time I have to put into testing so keeping state is unlikely to happen. However, I did just use the default ruleset which has very few rules so I would not expect much difference.

      When I have time for more testing I may well try some UDP packets.

  2. By Kevin Bowling (kev009) kevin.bowling@kev009.com on http://www.kev009.com/

    Is the moral of the story that the mp kernel has packet loss? I've got 2 atom d525 boxes running amd64.mp as gateways, is that a bad idea?

    Comments

    1. By Andrew Fresh (andrew) on http://www.afresh1.com

      In my testing and reported by others, yes, I got packet loss with bsd.mp that I haven't had time to file a proper bug report on. It does not seem to have much effect on real world traffic because it is a fairly low percentage.

    2. By Anonymous Coward (anon) on

      > Is the moral of the story that the mp kernel has packet loss?

      No. In a certain configuration on certain hardware running certain OS versions, a problem was seen. But you can't generalize from that without doing more testing and IME that's unusual.

      > I've got 2 atom d525 boxes running amd64.mp as gateways, is that a bad idea?

      MP involves some overheads not needed with UP, so you may do a bit better with UP on primarily kernel-based workloads, but unless you're seeing a particular problem, that most likely just translates to a bit lower peak performance.

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