OpenBSD Journal

OpenBSD 5.9 network improvements

Contributed by tj on from the gotta-go-fast dept.

There are no doubt many eyes on OpenBSD's continuing network SMP renovation. Hrvoje Popovski writes in to tell us about some performance testing he's been doing:

My name is Hrvoje Popovski, I'm a husband, a father of 3 little kids and network engineer at University of Zagreb University Computing Centre SRCE. Somewhere around the beginning of 2015, I got one server to play with that luckily had four em(4) (Intel I350) and two ix(4) (Intel 82599) onboard NICs. Around that time, developers started to throw out some interesting MP diffs, and I couldn't resist trying them. So I started to beg my boss and people around me to buy or lend me some PCs or servers to generate traffic with the MP diffs. I don't know how, but two Dell servers came to my lab...

I only had em(4) and ix(4), but since the myx(4) driver was where fun is, I bought a card that used it on eBay. At one point I suspected that bge(4) is faster than em(4), and for just a few dollars, I bought a dual-port BCM5720. Currently I have em, bge, ix and myx cards in that box. The variety of network cards allows me to monitor the progress and performance of the MP networking work. I love that box.

The generator and receiver in the examples can be one or two servers or any desktop PC that you have handy. In this case, the generator is running Ubuntu 14.04 LTS. For generating UDP traffic up to 14Mpps, I'm using pktgen. For generating TCP traffic up to 12Mpps, I'm using trafgen from netsniff-ng. For counting packets, I'm using ifpps on the sending and receiving Linux interfaces, together with netstat -i 1 on the OpenBSD box.

I'm also starting to use Cisco TREX generator, and when the basic setup is done, I think that this tool could be very good for testing MP PF performance.

This simple lab could be quite aggressive when playing with pktgen or the trex generator, and it's easy to set up and send bugs to developers! Through the 5.8 and 5.9 development, I had a setup like this:

OpenBSD net lab fully loaded.

IBM X3550 M4
2 x Intel(R) Xeon(R) CPU E5-2620 v2 @ 2.10GHz, 2400.00 MHz

/etc/rc.conf.local:

pf=NO
ddb.console=1
kern.pool_debug=0
net.inet.ip.forwarding=1
net.inet.ip.ifq.maxlen=8192
kern.maxclusters=32768

And here are the net performance results. Generator is pktgen with 64 byte UDP packets.

                 OpenBSD 5.8                                   OpenBSD 5.9

ix - Intel 82599
send             receive            receive | send             receive            receive
                 routed             bridged |                  routed             bridged
200kpps          200kpps            200kpps | 200kpps          200kpps            200kpps
400kpps          400kpps            400kpps | 400kpps          400kpps            400kpps
600kpps          600kpps            520kpps | 600kpps          600kpps            600kpps
700kpps          700kpps            520kpps | 700kpps          700kpps            620kpps
800kpps          550kpps            520kpps | 800kpps          690kpps            570kpps
1Mpps            640kpps            520kpps | 1Mpps            680kpps            490kpps
1.4Mpps          640kpps            520kpps | 1.4Mpps          680kpps            280kpps
4Mpps            640kpps            520kpps | 4Mpps            680kpps            280kpps
8Mpps            640kpps            520kpps | 8Mpps            680kpps            280kpps
14Mpps           640kpps            520kpps | 14Mpps           680kpps            280kpps


myx - 10G-PCIE2-8BL2-2S

send             receive            receive | send             receive            receive
                 routed             bridged |                  routed             bridged
200kpps          200kpps            200kpps | 200kpps          200kpps            200kpps
400kpps          400kpps            400kpps | 400kpps          400kpps            400kpps
600kpps          600kpps            510kpps | 600kpps          600kpps            580kpps
700kpps          630kpps            510kpps | 700kpps          640kpps            580kpps
800kpps          630kpps            510kpps | 800kpps          640kpps            580kpps
1Mpps            630kpps            510kpps | 1Mpps            640kpps            580kpps
1.4Mpps          630kpps            510kpps | 1.4Mpps          640kpps            580kpps
4Mpps            630kpps            510kpps | 4Mpps            640kpps            360kpps
8Mpps            630kpps            520kpps | 8Mpps            640kpps            360kpps
14Mpps           630kpps            530kpps | 14Mpps           640kpps            360kpps


em - Intel I350

send             receive            receive | send             receive            receive
                 routed             bridged |                  routed             bridged
200kpps          200kpps            200kpps | 200kpps          200kpps            200kpps
400kpps          400kpps            400kpps | 400kpps          400kpps            400kpps
600kpps          600kpps            500kpps | 600kpps          600kpps            600kpps
700kpps          620kpps            500kpps | 700kpps          700kpps            640kpps
800kpps          620kpps            500kpps | 800kpps          700kpps            600kpps
1Mpps            620kpps            500kpps | 1Mpps            700kpps            510kpps
1.4Mpps          620kpps            500kpps | 1.4Mpps          700kpps            410kpps


bge - Broadcom BCM5720

send             receive            receive | send             receive            receive
                 routed             bridged |                  routed             bridged
200kpps          200kpps            200kpps | 200kpps          200kpps            200kpps
400kpps          400kpps            400kpps | 400kpps          400kpps            400kpps
600kpps          600kpps            545kpps | 600kpps          600kpps            600kpps
700kpps          660kpps            545kpps | 700kpps          700kpps            650kpps
800kpps          660kpps            545kpps | 800kpps          720kpps            600kpps
1Mpps            660kpps            545kpps | 1Mpps            720kpps            520kpps
1.4Mpps          660kpps            545kpps | 1.4Mpps          710kpps            440kpps

Thanks for the detailed stats, Hrvoje.

Much work has been done, but there's still plenty left to do. Even in 5.9, the network stack is still under KERNEL_LOCK. The improvements shown here mainly come from the fact that the driver interrupt handler can run at the same time now. We're excited to see what possibilities will open when the work is complete and the lock can be removed. Still, it's good to see that there's steady progress being made in one of the areas everyone seems to be interested in.

(Comments are closed)


Comments
  1. By journeysquid (Tor) on http://www.openbsd.org/donations.html

    Great work. Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?

    Comments
    1. By Anonymous Coward (133.237.7.86) on

      > Great work. Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?
      >

      Also strange is that the numbers for routed are higher than bridged...

      Comments
      1. By phessler (92.206.52.143) phessler@openbsd.org on

        > > Great work. Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?
        > >
        >
        > Also strange is that the numbers for routed are higher than bridged...

        not strange at all. routed is the true way for packets to flow through the system.

    2. By karchnu (2001:660:4701:1001:de4a:3eff:fe01:3b44) karchnu@karchnu.fr on https://karchnu.fr

      > Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?
      >

      That's a very important step backward iiuc. Can someone can give us more details about it ?

      Comments
      1. By Martin (93.129.212.227) mpi@openbsd.org on

        > > Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?
        > >
        >
        > That's a very important step backward iiuc. Can someone can give us more details about it ?

        How is it backward? Aren't you seeing an improvement too in bridged mode.

        But maybe by "more details" you're asking why in bridged mode the numbers of transmitted packets per second drops when the sending side saturates the machine. If that's your question then I'd say that's certainly due to the extra queue introduced for bridge(4). This queue is only temporary. It is here to divide the network stack in independent pieces that can be taken out of the KERNE_LOCK one at a time.

        Comments
        1. By rjc (rjc) on

          > > > Am I understanding the chart correctly that there's been a significant regression with ix and myx on the receive bridge side?
          > > >
          > >
          > > That's a very important step backward iiuc. Can someone can give us more details about it ?
          >
          > How is it backward? Aren't you seeing an improvement too in bridged mode.
          >
          > But maybe by "more details" you're asking why in bridged mode the numbers of transmitted packets per second drops when the sending side saturates the machine. If that's your question then I'd say that's certainly due to the extra queue introduced for bridge(4). This queue is only temporary. It is here to divide the network stack in independent pieces that can be taken out of the KERNE_LOCK one at a time.

          Hi Martin,

          Some (including myself) see the lower number and automatically think "bad", so thank you for clarifying.

          Cheers,

          Raf

  2. By Denis (2001:7a8:b5ad::10:10) on

    Thank you Hrvoje. It seems you are testing with IPv4 (net.inet.ip.forwarding=1). Can you tell if numbers are even with IPv6, please ?

    Comments
    1. By Blake (2001:1b48:4:1337:cabc:c8ff:fe96:6d2f) on 2112.net

      > Thank you Hrvoje. It seems you are testing with IPv4 (net.inet.ip.forwarding=1). Can you tell if numbers are even with IPv6, please ?

      I'd be very interested to know if the fixed-length lookup for MPLS packets increases the performance significantly vs. variable-length IPv6/IPv4...

  3. By mxb (104.233.108.86) on

    Dobrij rezultat!
    Dobro da znate.

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