Network adapter.

Jon Tegner tegner at nada.kth.se
Fri Nov 10 08:34:01 EST 2000


Felix Rauch wrote:

> > I have done some further testing, using netpipe
> > (http://www.scl.ameslab.gov/Projects/ClusterCookbook/nprun.html). That
> > application sends packages of increasing size between two nodes, and
> > there is a drastic reduction in throughput when the size of the block
> > approaches around 5800 bytes. For 5780 bytes speed is 67.45 Mbps and
> > for 5800 bytes it is 1.34 Mbps. For increasing sizes it stays low (at
> > least up till 1e6 bytes (where I stopped)).
>
> I didn't follow this discussion closely, but this sounds like a
> problem with the duplex-configuration. Make sure that your cards and
> your switch have the same setting: Either everyone has full-duplex or
> everyone has half-duplex (full-duplex is better).

Thanks, that did help!

When we forced the switch to half duplex the code docent hang anymore. But
performance is not as good as on a full duplex network, so how can the cards be
forced to full duplex (tried the utility program supplied on diskette with the
cards but not possible to change from there)? And I thought the card should
always choose full duplex if it is possible (according to the specs the card can
handle full duplex)? That is, why does not the auto setting on the switch work?

/jon


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