Hi Jim, list
1) Your first question:
I opened a thread on this list two months or so ago about a similar
situation: when OpenMPI would use/not use libnuma.
I asked a question very similar to your question about IB support,
and how the configure script would provide it or not.
Jeff answerer it, and I asked him to post the answer in the FAQ,
which he kindly did (or an edited version of it):
http://www.open-mpi.org/faq/?category=building#default-build
The wisdom is that OpenMPI will search for IB on standard places,
and will use it if it finds it.
If you don't have IB on a standard place, then you can use the
switch --with-openib=/dir to force IB to be part of your OpenMPI.
If I understood it right, the bottom line is that you
only don't get IB if it is hidden, or doesn't exist.
2) Your second question:
As for the --enable-static question, I don't know the answer.
I defer this one to the OpenMPI developers.
I confess I have no explanation for why "-lrdmacm -libverbs"
are listed amongst the "Wrapper extra LIBS" when OpenMPI is configured
with --enable-static, but those IB library flags are absent
when --enable-static is not used.
(Maybe because the dynamic linker does a smarter search.)
I hope this helps,
Gus Correa
---------------------------------------------------------------------
Gustavo Correa
Lamont-Doherty Earth Observatory - Columbia University
Palisades, NY, 10964-8000 - USA
---------------------------------------------------------------------
Jim Kress wrote:
Is it correct to assume that, when one is configuring openmpi v1.3.2 and if
one leaves out the
--with-openib=/dir
from the ./configure command line, that InfiniBand support will NOT be built
into openmpi v1.3.2? Then, if an Ethernet network is present that connects
all the nodes, openmpi will use that network?
Also, is it required to add
--enable-static
to the ./configure command line to make sure Infiniband support is
available?
If I do not then the ompi_info --config command yields
Wrapper extra LIBS: -ldl -Wl,--export-dynamic -lnsl -lutil -lm -ldl
Note the absence of -lrdmacm and -libverbs which, I am told, are essential
for Infiniband support.
Whereas if --enable-static IS included, the ompi_info --config command
yields
Wrapper extra LIBS: -lrdmacm -libverbs -ldl -Wl,--export-dynamic -lnsl
-lutil -lm -ldl
And -lrdmacm and -libverbs are now present.
Thanks for your help.
Jim
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