Newsgroups: comp.parallel.mpi
From: Thomas Fuerle <fuerle@vipios.pri.univie.ac.at>
Subject: Re: shared-memory pentium-based multiprocessor
Organization: Vienna University, Austria
Date: Thu, 16 Jul 1998 13:01:14 +0200
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Message-ID: <35ADDD7A.9EE27491@vipios.pri.univie.ac.at>



Janche Sang wrote:

> We have a shared-memory 4-PentiumCPU multiprocessor running LINUX.
> I cannot install MPI if I configure the MPI either using
>     -device=ch_shmem
> or
>     -device=ch_p4 -comm=shared
>
> Any help will be appreciated.
>
> Janche
> ======

Hi everybody, this posting is one month ago, I tried out, and it works
on a single processor Linux machine. Hope, this helps.

Regards, Tom

-----------------------------------------------------------------------------------------

Subject:
             Guideline to configure MPICH with shmem on Linux
        Date:
             Tue, 23 Jun 1998 11:20:04 +0200
        From:
             Wolfram Webers <wwebers@cs.tu-berlin.de>
 Organization:
             TU-Berlin
  Newsgroups:
             comp.parallel.mpi




Ok, here's a small patch for mpich.

1. Edit the files

    mpid/ch_shmem/p2p_shmalloc.h

2. swap the lines:

/* Reluctant default: System V shared memory segments.  Look out for
ipcs. */
#if !defined(SHMEM_PICKED) && defined(HAVE_MMAP)
#    define USE_MMAP
#    define SHMEM_PICKED
#endif

/* If there is nothing special then we will use mmap if we have it. */
#if !defined(SHMEM_PICKED) && defined(HAVE_SHMAT)
#    define USE_SHMAT
#    define SHMEM_PICKED
#endif

into:

/* Reluctant default: System V shared memory segments.  Look out for
ipcs. */
#if !defined(SHMEM_PICKED) && defined(HAVE_SHMAT)
#    define USE_SHMAT
#    define SHMEM_PICKED
#endif

/* If there is nothing special then we will use mmap if we have it. */
#if !defined(SHMEM_PICKED) && defined(HAVE_MMAP)
#    define USE_MMAP
#    define SHMEM_PICKED
#endif

so on default the 'shmat' function is used.

3. If you like to use 'ch_lfshmem' you have to do so in ch_lfshmem

4. configure mpi with -device=ch_shmem or -device=ch_lfshmem

This was it. Note that you have to start your application now with

<appl> -np 2 ....

rather than with mpirun -np 2 <appl> ...

Ciao, Wolfram.

------------------------------------------------------------------------------------------------

--
Thomas Fuerle
mailto:fuerle@vipios.pri.univie.ac.at
http://vipios.pri.univie.ac.at
Institute for Applied Computer Science and Information Systems
University of  Vienna, Rathausstr. 19/4, A-1010 Vienna, Austria
Tel: +43 1 4277 38423

"Don't hate yourself in the morning -- sleep till noon."