Newsgroups: comp.parallel.mpi
From: "James B. White, III (Trey)" <trey@osc.edu>
Subject: Re: mpi,sgi  o200
Organization: Ohio Supercomputer Center
Date: Fri, 17 Oct 1997 09:58:19 -0400
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Message-ID: <34476EFB.6CE7F963@osc.edu>

Patrick STOCLET wrote:
> i use blocking sends and receive with a fixed pattern of
> communication

The problem is probably the blocking sends. You can get into a deadlock
situation if sends block and thus never get to the recieves that must be
executed in order for other sends to unblock.

A solution is to replace the blocking sends with non-blocking sends.

Instead of something like this: 

	MPI_Send
	...
	MPI_Recv

... do this:

	MPI_Isend
	...
	MPI_Recv
	MPI_Wait  /* for the Isend to complete */
-- 
James B. White, III (Trey)
Ohio Supercomputer Center
trey@osc.edu
<http://www.osc.edu/~trey/>
Phone: (614)292-9291  Fax: (614)292-7168