Well, this is embarrassing... It seems that in my haste to blame the Linux Bridge, I discovered that the real problem was an Ethernet Cable, more specifically, the one connecting the Linux Box to the PC B. Recentl, I changed the location of the Router/server and during that change, I must have accidentally damaged on cable. Before that, I repeated the iperf3 test several times and from time to time, the performance fluctuated between 5 and 40 Mbps. Because of that, I decided to change the Ethernet Cables just to check it. After installing the new cable, the performance is now what was expected... I'm sorry to have wasted your time... I hope this helps future generations not to be so hasty... On 27 December 2015 at 20:05, Florian Pritz <bluewind@xinu.at> wrote:
On 27.12.2015 19:23, Carlos Ferreira wrote:
I'm using Arch Linux in a SuperMicro A1SAi-2750F motherboard and I'm having performance issues while bridging 3 Ethernet Gigabit network interfaces. The 4th network interface of that motherboard, is used to connect to the ISP. [..] I conducted a small iperf3 test. The scenario was: PC A (100Mbps) <---> Server Ether 1(1Gbps) <---> Linux Bridge (br0) <---> Server Ether 2 (1Gbps) <---> PC B (1Gbps)
Are these values from a tool like ethtool or are they just what you think they should be? I've sometimes had bad cables/connectors cause speeds to be limited to 100Mbit instead of gbit.
As for software problems you'd need to provide/look at some more details like cpu load, interrupts, top, htop, dstat -lpma, mpstat -I ALL, dmesg. That cpu should be able to easily handle gbit speed though and a bridge in linux should be able to far exceed your network speeds.
Hope that helps, Florian
-- Carlos Miguel Ferreira Researcher at Telecommunications Institute Aveiro - Portugal Work E-mail - cmf@av.it.pt Skype & GTalk -> carlosmf.pt@gmail.com LinkedIn -> http://www.linkedin.com/in/carlosmferreira