Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

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 -

    http://blogs.cisco.com/ciscotalk/performance/comments/ibarrier/

-- 
Jeff Squyres
jsquyres_at_[hidden]
For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/