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Subject: Re: [OMPI devel] Using MTT to test the newly added SCTP BTL
From: Karol Mroz (kmroz_at_[hidden])
Date: 2007-11-30 18:51:23

Hash: SHA1

Hi, Jeff... thanks for getting back to me.

Jeff Squyres wrote:
> On Nov 29, 2007, at 12:13 PM, Karol Mroz wrote:
>>> One solution might be to remove the .ompi_ignore but to only enable
>>> the SCTP BTL when an explicit --with-sctp flag is given to configure
>>> (or something similar). You might want to run this by the [OMPI]
>>> group first, but there's precedent for it, so I doubt anyone would
>>> object.
>> The situation at present is that the SCTP BTL only builds on FreeBSD,
>> OSX and Linux and only if the SCTP is found to be in a standard place.
>> On Linux, for instance, you need to have installed the lksctp
>> package in
>> order for the SCTP BTL to build. We also have a --with-sctp configure
>> option where you can specify the SCTP path should it not be in a
>> standard location. If SCTP does not exist on the system, then the BTL
>> will not build and more importantly, will not break the build of the
>> overall system.
> Is this SCTL lksctp package installed by default on any Linux? OS X?
> Solaris?

The lksctp package is not installed by default on any Linux distribution
that I'm aware of. For OSX, SCTP support is provided via the SCTP
Network Kernel Extension ( and
this too is not installed by default. Solaris does have SCTP support by
default, but we currently do not build on Solaris systems regardless.

>> My question now, is it necessary for us to alter the above
>> behavior (as initially mentioned by Jeff), or is having the SCTP BTL
>> build iff SCTP is found sufficient?
> I think the only thing that matters is what the current default
> behavior is -- if the .ompi_ignore is removed, will it hose anyone
> unexpectedly? I.e., if they build and run today and it works, then
> the .ompi_ignore is removed and you build and run... and it doesn't
> work. That my only real concern.

Removal of .ompi_ignore should not create build problems for anyone who
is running without some form of SCTP support. To test this claim, we
built Open MPI with .ompi_ignore removed and no SCTP support on both an
ubuntu linux and an OSX machine. Both builds succeeded without any problem.

A couple other questions we had, and this references an email from a
while back, deals with SCTP BTL exclusivity. I will link the relevant
message below and any advice would be appreciated:


- --
Karol Mroz

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