Network adapter.

Pierre Brua brua at
Wed Nov 8 05:55:08 PST 2000

Jon Tegner wrote:
> We have the A1 release, and the cards work - that is we get decent
> communication speeds between two nodes. But if more than two nodes are
> involved in calculations the speed goes down drastically (sometimes to
> a complete stop). (This specific application runs with good
> performance on other beowulfs.)

I think that you have a problem with your switch :
The maximum aggregate bandwidth available is too low to sustain high
troughput transfer between more than 2 nodes. Which switch brand and
model do you use for your cluster ?

> We are using the latest via-rhine from, but in
> reference to the comment above we wonder if the lousy performance can
> be a result of the DFE-530TX cards? Or is it likely something else is
> causing this kind of problem? (And if we have to by new cards, would
> the 3c905b-tx be a good choice?).

It would be a good choice as far as I know, but I consider your problem
lies mainly in the switch : the cards change would solve nothing.

If you problem is more related to a low throughput with the master node,
using a second NIC and port trunking or switching the master node to
gigabit instead of fast ethernet may help, but I need a more complete
description of your application to help you there.

Pierre BRUA
          PARALLINE          ///        Parallelism & Linux
71,av. des Vosges Phone:+33 388 141 740 mailto:brua at
F-67000 STRASBOURG  Fax:+33 388 141 741

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