Title: RE: [openib-general] ip over ib throughtput
First, I love Hardware Reliability.

1QP per node, this might be fine for small clusters, but what about larger clusters, where I have an all-to-all communications pattern ? What about say *IF* something like IB was ever designed into a BG/L class cluster ? What about if I happen to want to run a multi-protocol application, how is that currently handled ? *IF* I am allowed to do that and I had an all-2-all communication pattern, looks like I would exhaust the QP allocation table. Sounds like potentially, as clusters/nodes increase in number, we could easily bump our heads on some of the IBTA artificial limits set. IMHO

Instead of 1 QP for every node, don't you mean 1 QP for every HCA/Node ? That assumes that I can have multiple HCAs per node. Currently even at the IPoIB level, we can not do "bonding/trunking", correct ?

Steve...

At 12:11 PM -0800 1/5/05, Diego Crupnicoff wrote:
> -----Original Message-----
> From: Woodruff, Robert J [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, January 05, 2005 3:53 PM
> To: Diego Crupnicoff; Hal Rosenstock; Peter Buckingham
> Cc: [email protected]
> Subject: RE: [openib-general] ip over ib throughtput
>
>
> The trade off is that a fully connected model requires each
> node to burn a QP for every node in the cluster and thus does
> not scale as well as the UD model.  My guess is that if
> people need really high performance
> socket access, they will use SDP instead.
>
> woody
>
1 QP for every node in the cluster does not sound that bad.
SDP is a good alternative too. It has even further benefits as compared to IPoIB (built in HW reliability that eliminates the TCP/IP stack, potential for zero copy, etc). However, in terms of QP requirements, SDP would consume even more than what a connected mode IPoIB would (still not too bad given the IB HW capabilities).
Diego



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