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Subject: Re: [OMPI users] opal_os_dirpath_create: Error: Unable to create the, sub-directory
From: Ralph Castain (rhc_at_[hidden])
Date: 2014-02-05 11:38:31


I'm afraid it isn't quite that simple, Jeff. We also have the race condition at startup - multiple procs on the same machine, from the same job, will be trying to create the session directory tree. At the moment, we see the fact that some other proc created it and simply create our own entry underneath as required. So I don't know how to tell the difference between "some other proc from my job created it first" vs "this is a stale directory and should be deleted".

However, I might be able to rig something up when the daemons start, and for singletons. Will give that a try

On Feb 4, 2014, at 6:11 AM, Jeff Squyres (jsquyres) <jsquyres_at_[hidden]> wrote:

> On Feb 3, 2014, at 6:44 PM, Ralph Castain <rhc_at_[hidden]> wrote:
>
>>> If I may suggest to test the behavior of 1.7.x... what about this: Have a test case that creates a bunch of files (from 0 to 65536) in /tmp/openmpi-sessions-${USER}... before launching an executable without mpirun... >:)
>>
>> Ick - it will actually only conflict if/when the pid's wrap, so it's a pretty rare issue.
>
>
> Ralph: what do you think about modifying this for 1.7.5? I.e., if the pid dir already exists in the session directory, remove it. This is always safe to do (assuming /tmp is a local filesystem) because the OS will never use the same PID for 2 concurrent processes.
>
> --
> Jeff Squyres
> jsquyres_at_[hidden]
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