Subject: Re: Qube2 Network Performance & Forwarding
To: Francis Koclas <>
From: Andy Ruhl <>
List: port-cobalt
Date: 04/26/2006 21:44:16
On 4/26/06, Francis Koclas <> wrote:
> I have a couple questions related to these numbers;
> 1) What is causing the rather slow speeds in I and II? The Qube2's CPU
> remains 100% idle while it forwards. In linux (debian 3.1 with kernel
> 2.4.28 i think) it makes the Qube2 roughly 80% idle and the speeds get
> bumped to a little bit more than 6 MB/s.
> 2) Is this a problem specific to the built-in 21143 chips?
> 3) Why is one way slower than the other? Even if I swap the
> ifconfig.tlp0 and ifconfig.tlp1, and swap the network cables, the same
> thing happens, so tlp0 is not any faster than tlp1 or whatever. The NICs
> on the workstations are very capable and they're not the bottleneck here
>   (Sun Gem in WorkstationA, 3c905C in WorkstationB). As you can see they
> can pretty much saturate 100baseTX..
> 4) Is there any cobalt specific tweaking to improve network performance?
> 5) What are good, known to work PCI NICs for the Qube2? I tried a 3Com
> 3c905C and I only get a couple KB/s with it.. Also, anyone tried dual
> ports cards? I would ask for quad ports too, but I doubt those would
> actually fit in there.

There's a known performance problem with the PCI bus on the Qube with
NetBSD. Unfortunately, the fix is not known as far as I know. The
problem either doesn't exist or isn't as bad with Linux.

I don't know much more