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Subject: Re: [OMPI devel] New address selection for btl-tcp (was Re: [OMPI svn] svn:open-mpi r17307)
From: Brian W. Barrett (brbarret_at_[hidden])
Date: 2008-02-22 12:14:26

On Fri, 22 Feb 2008, Adrian Knoth wrote:

> I see three approaches:
> a) remove lo globally (in if.c). I expect objections. ;)

I object! :). But for a good reason -- it'll break things. Someone
tried this before, and the issue is when a node (like a laptop) only has
lo -- then there are no reported interfaces, and either there needs to be
lots of extra code in the oob / btl or things break. So let's not go down
this path again.

> b) print a warning from BTL/TCP if the interfaces in use contain lo.
> Like "Warning: You've included the loopback for communication.
> This may cause hanging processes due to unreachable peers."

I like this one.

> c) Throw away on the remote side. But when doing so, what's
> the use for including it at all?

This seems hard.