Newsgroups: comp.parallel.mpi
From: A Gordon Smith <smith@epcc.ed.ac.uk>
Subject: Re: Memory Leak in MPI for Cray Release 1.4a?
Organization: Edinburgh Parallel Computing Centre
Date: Thu, 11 Jul 1996 09:39:57 GMT
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Message-ID: <31E4CBED.41C67EA6@epcc.ed.ac.uk>

Christopher Ditchman wrote:
> 
> Hello,
> 
> I was wondering if anyone has heard of / can confirm the existence
> of a memory leak existing in MPI for the Cray T3D (release 1.4a)
> involving derived datatypes not being freed properly.
> 
> The Cray consultants on lab seem to agree that the code I am
> using is correct and that a memroy leak is within MPI.  The
> main program is written in FORTRAN 77 and makes use of
> a genetic algorithm library (which uses MPI) written in C.
>


Hello Chris,

A problem similar to yours has been reported by staff at JPL;
perhaps they were referring to the problem that you describe.
The problem is under investigation and we have yet to confirm
whether there is a memory leak problem with MPI datatype
construction and freeing in release 1.4a and the current release
1.5a.
 
> Do later versions of MPI fix the memory leak?  Are there work
> arounds for this sort of problem?  Right now I am faced with
> the prospect translating all of the FORTRAN to C in order to
> change all variables from 64 to 32 bits to forstall the
> inevitable memory failure.  I am also considering switching to
> PVM.  Ideally, I would like to retain as much of the FORTRAN as
> possible.
> 


If you contact us as at the following address we can try and help
you. I suspect that there are much easier ways to get around this
problem than changing from Fortran to C.

The proper mechanism for sending queries and reporting problems on
the CRI/EPCC MPI for Cray T3D software is to contact local T3D
support staff in the first instance; you/they can contact the
following e-mail address for assistance.

          t3dmpi@epcc.ed.ac.uk


More information on the CRI/EPCC MPI for Cray T3D software is
available at the following URL:

          http://www.epcc.ed.ac.uk/t3dmpi/Product/


thanks,
-- 
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 -=-=- A. Gordon Smith -=- Edinburgh Parallel Computing Centre -=-=-
 =- http://www.epcc.ed.ac.uk/~smith -=- Phone +44 (0)131 650 6712 -=
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