Re: 3Com 905C very slow (400Kbps)

On Mon, 2 Jun 2003, Florian Hackenberger wrote:

> The mii-diag says that autonegotiated media type is 100baseTX-FD. I'm
> using an US Robotics Hub.

Unless this is a _switching_ hub a.k.a. switch, the FD media setting is 
wrong and would perfectly explain what you are seeing.

> With NFS the throughput is about 300-500Mbps.

If you'd post something like this on the Linux NFS list you'll be regarded 
as a hero :-) I assume that you wanted to say Kbps instead of Mbps.

> The 3Com card doesn't drop or overrun packets (ifconfig claims that).

Could you post the content of /proc/net/dev file ? (after seeing this 
behaviour for some time)

> Is the CPU to slow for the network card, or something else?

Yes, it might. And quite a lot of mainboards from that era had PCI 
problems... PCI problems are usually disruptive and so they are reported 
by the driver - do your logs contain some messages from the network card ?

You could try to use ttcp or netperf or something similar to find what 
speed the computer is able to sustain with pure network load (= without 
disks being involved).

> I've tried the Realtek 8139C (which should be worse) as well...same
> result.

This would likely indicate either the computer itself or the link (cable, 
hub/switch) as being responsible.

-- 
Bogdan Costescu

IWR - Interdisziplinaeres Zentrum fuer Wissenschaftliches Rechnen
Universitaet Heidelberg, INF 368, D-69120 Heidelberg, GERMANY
Telephone: +49 6221 54 8869, Telefax: +49 6221 54 8868
E-mail: [email protected]

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