From: Yon Han CHONG <Y.H.Chong@cranfield.ac.uk>
Newsgroups: comp.parallel.mpi
Subject: Re: How many to allocate buffer sizes in Nonblocking,
    bufferd-mode communication?
Date: Wed, 25 Nov 1998 11:29:33 +0100
Organization: Cranfield University
Message-Id: <365BDC0D.B6BF9081@cranfield.ac.uk>
References: <36595769.355C28C4@juno.cs.pusan.ac.kr>
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"Jun, Sun-Mi" wrote:
> 
> Hi Everyone
> 
> I have been implementing a Nonblocking communication program.
> (I'm using MPI_Buffer_attach(), MPI_Ibsend(), MPI_Buffer_dettach() )
> 
> The size requested for the buffer is 4096 bytes but,
> the run-time error occurs,
> the system displays error message " Unavailable space........."  and
> abort the program.
> 
> My system platform is linux-based and 586, 32MB memory, sufficient disk
> space.
> 
> Is there a limit size in nonblocking communication buffer ?
> (I couldn't find the comment for buffer size )
> 
Is it necessary to attach buffers? Can't you construct a new datatype?
This will use less memory since you are not dupicating data to put into
a buffer. This also speed up your program since:

1. again, no need to dupicate data
2. and you can require persistent communication.

-- 
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Yon Han CHONG                     |
Flow Control and Prediction Group | Tel: + 44 1234 750 111 ext. 5420
Cranfield College of Aeronautics  | E-mail: Y.H.Chong@cranfield.ac.uk
Cranfield University              | Fax: + 44 1234 752 149
United Kingdom                    | Mobile: + 44 958 381 395
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