It's used for compressing the startup time messages in PMIx. I.e., the traffic
for when you "mpirun ...".
It's mostly beneficial when launching very large MPI jobs. If you're only
launching across several nodes, the performance improvement isn't really
noticeable.
--
Jeff Squyres
jsquy...@cisco.com
From: users on behalf of Matt Thompson via
users
Sent: Monday, January 31, 2022 10:53 AM
To: Open MPI Users
Cc: Matt Thompson
Subject: [OMPI users] Building Open MPI without zlib: what might go
wrong/different?
Open MPI List,
Recently in trying to build some libraries with NVHPC + Open MPI, I hit an
error building HDF5 where it died at configure time saying that the zlib that
Open MPI wanted to link to (my system one) was incompatible with the zlib I
built in my libraries leading up to HDF5. So, in the end I "fixed" my issue by
adding:
--without-zlib
to my configure line for Open MPI and rebuilt. And hey, it worked. HDF5 built.
And Hello world still works as well.
But I'm now wondering: what might I be missing now? Zlib isn't required by the
MPI Standard (as far as I can tell), so I'm guessing it's not functionality but
rather performance?
Just curious,
Matt
--
Matt Thompson
“The fact is, this is about us identifying what we do best and
finding more ways of doing less of it better” -- Director of Better Anna
Rampton
