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Subject: Re: [OMPI users] MPI_Reduce performance
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2010-09-22 08:59:50

On Sep 9, 2010, at 4:31 PM, Ashley Pittman wrote:

>> What is the exact semantics of an asynchronous barrier,
> I'm not sure of the exact semantics but once you've got your head around the concept it's fairly simple to understand how to use it, you call MPI_IBarrier() and it gives you a handle you can test with MPI_Test() or block for with MPI_Wait(). The tricky part comes in how many times you can call MPI_IBarrier() on a communicator without waiting for the previous barriers to complete but I haven't been following the discussion on this one to know the specifics.

FWIW: here's a brief writeup of MPI_Ibarrier -

Jeff Squyres
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