[arch-general] Performance with Linux Bridge

[Carlos Ferreira]

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 at 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 at av.it.pt
Skype & GTalk -> carlosmf.pt at gmail.com
LinkedIn -> http://www.linkedin.com/in/carlosmferreira