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Subject: Re: [OMPI devel] Warning on fork() disappears if I use MPI threads!!
From: N.M. Maclaren (nmm1_at_[hidden])
Date: 2010-11-29 14:30:09

On Nov 29 2010, George Bosilca wrote:
> If your code doesn't exactly what is described in the code snippet
> attached to your previous email, then you can safely ignore the warning.
> In fact, any fork done prior to the communication is a non-issue, but it
> is difficult to identify. Therefore, we output the warning as soon as we
> detect a fork after MPI_Init.

USUALLY a non-issue.

> You can find more information about the usage of fork in Open MPI at

Yes. It says about as much as can be said, except between consenting
geeks in private! Well, I suppose that this mailing list counts :-)

I have had trouble with systems that sent signals to process groups
and/or all processes with a particular controlling terminal, and even
operating system 'super groups', where the location of the fork won't
save you. I can't see how to describe that issue in terms that make
sense to most users.

Nick Maclaren.