Re: Ethernet over Kernel Sockets

[Pavel Machek]

On Fri 2008-02-29 21:54:21, Lukas Razik wrote:
> Hello all!
> 
> As you know, some network cards doesn't have a 'eth' 
> interface under linux.
> Because of that I'm developing a net_device based driver 
> which doesn't transmit and receive directly through a 
> real network card but through UDP kernel sockets.

What is it good for?

> So the eth1 interfaces are based on sockets which use 
> the eth0 (Gigabit) interfaces for the communication.
> Now, if I measure the transmission between 192.168.0.1 
> and 192.168.0.2 then I get transmission rates that are 
> normal for Gigabit-Ethernet (~25?sec (PingPong) and 
> ~900Mbit/s).
> If I measure the transmission through the eth1 
> interfaces between 192.168.1.1 and 192.168.1.2 then I 
> only get ~1msec (PingPong) and only about ~400Mbit/s.
> 
> The interesting thing is, that I always get PingPongs of 
> 1ms (= one jiffie). Although if I measure with 100MBit- 
> or other non-Ethernet cards.

Try increasing HZ :-)... or maybe it is a gigabit interrupt mitigation
issue?

-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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