[Beowulf] Infiniband modular switches

Gilad Shainer Shainer at mellanox.com
Tue Aug 26 12:50:06 PDT 2008

Dan Kidger wrote:
> Gilad wrote:
> > It was proven by the same person who did the slides you 
> referred to, 
> > when doing the same testing on IB DDR we got much better 
> results with 
> > IB versus Quadrics. your theory does not really meet reality.
> Care to describe to the list what these results were, and to 
> speculate about why IB gave better results?
> Daniel

Sure. My intend was not to compare between IB and Quadrics, but to show
that the network/host injection rate is very relevant in contention
tests. For given host injection rate, increase in network capability
reduces the contention (assuming finite number of hosts.....). As for
the numbers:

Send ave: IB SDR 263MB, Quadrics 369MB, IB DDR 453MB
Receive ave: IB SDR 340MB, Quadrics 370MB, IB DDR 547MB

I noticed that Quadrics decided to use just part of those numbers for
their poster at ISC ...  ;-)


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