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From: Gleb Natapov (glebn_at_[hidden])
Date: 2007-10-25 10:35:07

On Wed, Oct 24, 2007 at 08:01:44PM -0400, Jeff Squyres wrote:
> My proposal is that the "connect" field can be added to the INI file
> and take a comma-delimited list of values of acceptable CPCs for a
> given device. For example, the ConnectX HCA can take the following
> value:
> connect = xrc, rdma_cm, oob
> Meaning:
> - first, try the XRC CPC to try to make the connection
> - if that fails, try the RDMA CM CPC
> - if that fails, try the OOB CPC
> - if that fails, fail the connection
I don't think xrc should be used by default even if HW supports it. Only if
special config option is set xrc should be attempted. And xrc availability
can be tested in runtime without additional options in ini file.
I don't know iWarp enough to tell if it is possible to find out in
runtime if rdma_cm is mandatory or other means of connection
establishment can be used, but if there is no way to do it, then new
parameter "hca_type" could be added to ini file with two possible
values "ib" and "iwarp".

> iWARP-based NICs can use the following value:
> connect = rdma_cm
> If no "connect" value is specified, then default value of "oob,
> rdma_cm" can be assumed (possibly someday changing to "rdma_cm, oob").
> I mention this here on the devel list because disparate groups are
> working on different CPC's; coordination will be required to
> implement this arbitration mechanism.
> Comments?