[Bug 894608] Re: Implementing a bridge slows 10G network

Serge Hallyn 894608 at bugs.launchpad.net
Fri Nov 25 17:50:14 UTC 2011


Thanks for reporting this bug.  I've marked it as also affecting the
kernel as the bridge driver seems most likely to be the problem.


** Changed in: bridge-utils (Ubuntu)
   Importance: Undecided => Medium

** Also affects: linux (Ubuntu)
   Importance: Undecided
       Status: New

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Title:
  Implementing a bridge slows 10G network

Status in “bridge-utils” package in Ubuntu:
  New
Status in “linux” package in Ubuntu:
  New

Bug description:
  Installing bridge-utils and then setting up a bridge in
  /etc/netwrok/interfaces decimates my netwrok speed. Uninstalling the
  package and doing a reboot restores the speed.

  This bug was originally posted here:
  https://bugs.launchpad.net/qemu/+bug/861141 but I now realise it is
  bridge-utils specific.

  Hardware:
  I have two identical machines (DELL poweredge R815), each with Broadcom NetXtreme II BCM57711 10-Gigabit PCIe connected via a 10G switch.
  Each machine runs 4 socket 12 core AMD Opteron(tm) Processor 6174 and 128GB of ram

  Software:
  Both machines ar running ubuntu server 10.04 lts Kernels are:
  Linux whitlam 2.6.32-28-server #55-Ubuntu SMP Mon Jan 10 23:57:16 UTC 2011 x86_64 GNU/Linux
  Linux fraser 2.6.32-28-server #55-Ubuntu SMP Mon Jan 10 23:57:16 UTC 2011 x86_64 GNU/Linux

  I have installed iperf on both machines.

  The tests here involve running whitlam as the iperf server and fraser as the client.
  On whitlam I run:
  bioadmin at whitlam:~# iperf -sm

  On fraser I run:
  bioadmin at fraser:~# iperf -c whitlam -d

  before installation I get:
  bioadmin at whitlam:~# iperf -sm
  ------------------------------------------------------------
  Server listening on TCP port 5001
  TCP window size: 85.3 KByte (default)
  ------------------------------------------------------------
  [ 5] local 10.168.48.14 port 5001 connected with 10.168.48.13 port 37960
  ------------------------------------------------------------
  Client connecting to 10.168.48.13, TCP port 5001
  TCP window size: 110 KByte (default)
  ------------------------------------------------------------
  [ 6] local 10.168.48.14 port 49627 connected with 10.168.48.13 port 5001
  Waiting for server threads to complete. Interrupt again to force quit.
  [ 5] 0.0-10.0 sec 10.8 GBytes 9.23 Gbits/sec
  [ 5] MSS size 1448 bytes (MTU 1500 bytes, ethernet)
  [ 6] 0.0-10.0 sec 10.6 GBytes 9.11 Gbits/sec
  [ 6] MSS size 1448 bytes (MTU 1500 bytes, ethernet)

  Which is nice.

  Next I run:

  sudo aptitude -y install bridge-utils

  and then I add a bridge to the interfaces file like thus:

  FROM:
  # This file describes the network interfaces available on your system
  # and how to activate them. For more information, see interfaces(5).

  # The loopback network interface
  auto lo
  iface lo inet loopback

  # The primary network interface
  auto eth4
  iface eth4 inet static
   address xx.xx.xx.xx
   netmask 255.255.255.0
   network xx.xx.xx.0
   broadcast xx.xx.xx.255
   gateway xx.xx.xx.1
   # dns-* options are implemented by the resolvconf package, if installed
   dns-nameservers blah blah

  TO:

  # This file describes the network interfaces available on your system
  # and how to activate them. For more information, see interfaces(5).

  # The loopback network interface
  auto lo
  iface lo inet loopback

  # The primary network interface
  #auto eth4
  #iface eth4 inet manual

  auto br0
  iface br0 inet static
   address xx.xx.xx.xx
   netmask 255.255.255.0
   network xx.xx.xx.0
   broadcast xx.xx.xx.255
   gateway xx.xx.xx.1
   bridge_ports eth4
   bridge_stp off
   # dns-* options are implemented by the resolvconf package, if installed
   dns-nameservers blah blah

  And restart networking

  sudo /etc/init.d/netwroking restart

  Which results in:
  bioadmin at whitlam:~# iperf -sm
  ------------------------------------------------------------
  Server listening on TCP port 5001
  TCP window size: 85.3 KByte (default)
  ------------------------------------------------------------
  [ 4] local 10.168.48.14 port 5001 connected with 10.168.48.13 port 56405
  ------------------------------------------------------------
  Client connecting to 10.168.48.13, TCP port 5001
  TCP window size: 1.25 MByte (default)
  ------------------------------------------------------------
  [ 6] local 10.168.48.14 port 57001 connected with 10.168.48.13 port 5001
  Waiting for server threads to complete. Interrupt again to force quit.
  [ ID] Interval Transfer Bandwidth
  [ 4] 0.0-10.0 sec 10.5 GBytes 9.00 Gbits/sec
  [ 4] MSS size 1448 bytes (MTU 1500 bytes, ethernet)
  [ 6] 0.0-10.0 sec 2.51 GBytes 2.15 Gbits/sec
  [ 6] MSS size 1448 bytes (MTU 1500 bytes, ethernet)

  Note that the connection from the machine with bridge-utils installed
  (fraser) to the other machine (whitlam) is not affected. Only the
  connection from whitlam to fraser.

  Both machines are fresh installs with nfs-common, iperf installed.
  Fraser also has bridge-utils

  Any help is very much appreciated!

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