This repository was archived by the owner on Sep 30, 2022. It is now read-only.
v2.0.1: odls_default: do not opal_output() while creating a process! #1190
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
It is verbotten to use opal_output() after the fork() but before the exec()! It results in all manner of undefined behavior. For example, on some OS X systems, if you run a trivial "hello world" MPI program with a high level of ODLS verbosity: ```sh $ mpirun -np 3 --mca odls_base_verbose 100 ./hello_c ``` You will see a bunch of output from the mpirun ODLS base, but then it *may* hang in odls_default_module.c:do_child() -- after the fork() but before the exec() -- while trying to opal_output() some debugging statements. The solution is to remove these extraneous opal_output() statements. Indeed, the ODLS base is already outputting the same information that these opal_output() statements are trying to emit, anyway. Signed-off-by: Jeff Squyres <jsquyres@cisco.com> (cherry picked from commit open-mpi/ompi@dd9a819)
|
Test PASSed. |
|
👍 |
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
5 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
It is verbotten to use opal_output() after the fork() but before the
exec()! It results in all manner of undefined behavior. For example,
on some OS X systems, if you run a trivial "hello world" MPI program
with a high level of ODLS verbosity:
You will see a bunch of output from the mpirun ODLS base, but then it
may hang in odls_default_module.c:do_child() -- after the fork() but
before the exec() -- while trying to opal_output() some debugging
statements.
The solution is to remove these extraneous opal_output() statements.
Indeed, the ODLS base is already outputting the same information that
these opal_output() statements are trying to emit, anyway.
Signed-off-by: Jeff Squyres jsquyres@cisco.com
(cherry picked from commit open-mpi/ompi@dd9a819)
@hppritcha This is safe for v2.0.1 because a) it only happens on some systems, and b) it's fairly esoteric to run with
odls_base_verbose>10 (which is what causes the problem).@rhc54 Please review for v2.0.1.