Re: [Boost-users] [mpi] irecv / send problem

Subject: Re: [Boost-users] [mpi] irecv / send problem
From: Ryo IGARASHI (rigarash_at_[hidden])
Date: 2009-06-13 01:01:32

Hi, Nick,

# I am not a MPI expert.

On Sat, Jun 13, 2009 at 4:16 AM, Nick Collier<nick.collier_at_[hidden]> wrote:
> I running into an issue where an irecv followed by a send results in
> deadlock. A simple test case,

> Run with mpirun -np 2, this never completes. It does complete with
> vector<Item> msg(10) however.

According to the MPI standard, MPI_irecv() finishes when MPI_wait() is calledg,
and MPI_send() never returns before receive completes.
So the deadlock is of no surprise.

I think you shouldn't rely on the behavior with small size object.
It is the buffering mechanism in the MPI implementation
that avoid the deadlock of the small size object case.

See http://www.mpi-forum.org/docs/ for specification.

Best regards,
-- 
Ryo IGARASHI, Ph.D.
rigarash_at_[hidden]