From 842f8c128662714db586a06b52e136d3246df5a9 Mon Sep 17 00:00:00 2001 From: Jeff Squyres Date: Mon, 27 Feb 2017 17:15:34 -0500 Subject: [PATCH] README: Add more info about "backwards compatibility" Add more clarifying statements about our definition of "backwards compatibility" -- adding an example with static linking and another with containers. Signed-off-by: Jeff Squyres --- README | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/README b/README index 8fe570109a..351639bb98 100644 --- a/README +++ b/README @@ -8,7 +8,7 @@ Copyright (c) 2004-2008 High Performance Computing Center Stuttgart, University of Stuttgart. All rights reserved. Copyright (c) 2004-2007 The Regents of the University of California. All rights reserved. -Copyright (c) 2006-2016 Cisco Systems, Inc. All rights reserved. +Copyright (c) 2006-2017 Cisco Systems, Inc. All rights reserved. Copyright (c) 2006-2011 Mellanox Technologies. All rights reserved. Copyright (c) 2006-2012 Oracle and/or its affiliates. All rights reserved. Copyright (c) 2007 Myricom, Inc. All rights reserved. @@ -1464,6 +1464,20 @@ processes in a single MPI job. If the versions are not exactly the same everywhere, Open MPI is not guaranteed to work properly in any scenario. +Backwards compatibility tends to work best when user applications are +dynamically linked to one version of the Open MPI / OSHMEM libraries, +and can be updated at run time to link to a new version of the Open +MPI / OSHMEM libraries. + +For example, if an MPI / OSHMEM application links statically against +the libraries from Open MPI vX, then attempting to launch that +application with mpirun / oshrun from Open MPI vY is not guaranteed to +work (because it is mixing vX and vY of Open MPI in a single job). + +Similarly, if using a container technology that internally bundles all +the libraries from Open MPI vX, attempting to launch that container +with mpirun / oshrun from Open MPI vY is not guaranteed to work. + Software Version Number -----------------------