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@xxxxxxx> 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@xxxxxxxx Skype & GTalk -> carlosmf.pt@xxxxxxxxx LinkedIn -> http://www.linkedin.com/in/carlosmferreira
