netgear gigabit tuning

Felix Rauch rauch at
Tue Apr 17 06:32:42 EDT 2001

On Mon, 16 Apr 2001, Chris Black wrote:
> We have just installed a netgear 4-port copper gigabit switch and are using 
> it with netgear GA620T cards. We are trying to get maximum performance out 
> of this equipment. What I am looking for is tuning instructions for gigabit 
> cards. I have already done:
> echo 262144 > /proc/sys/net/core/rmem_max
> echo 262144 > /proc/sys/net/core/wmem_max
> As directed on the AceNIC driver page. I was unable to get transfers to work 
> when I tried increasing the mtu to 9000 for jumbo frame support though.
> Right now I get around 39MB/s transfer rate. I am hoping to improve this. 
> What type of numbers do other people with gigabit ethernet setups get?

It might well be that your reached the maximum performance for your
processor / memory / CPU / OS setup. With our Hamachi GNIC-II Gigabit
Ethernet cards we reached about 40 MB/s on 400 MHz/PIII and 2.2.x
kernels. The same cards achieve over 100 MB/s with our new 1 GHz/PIII
machines and a linux 2.4.3 kernel.

AFAIK the 2.4.x kernels have a better TCP/IP stack so you might want
to check out newer kernel if you are still using 2.2.x.

- Felix
Felix Rauch                      | Email: rauch at
Institute for Computer Systems   | Homepage:
ETH Zentrum / RZ H18             | Phone: ++41 1 632 7489
CH - 8092 Zuerich / Switzerland  | Fax:   ++41 1 632 1307

Beowulf mailing list, Beowulf at
To change your subscription (digest mode or unsubscribe) visit

More information about the Beowulf mailing list