automatic parallelization - summery

From: Zilberman Silviu <silviu # - at - # post.tau.ac.il>
Organization: TAU
Subject: automatic parallelization - summery
Date: Mon, 03 Dec 2001 06:49:34 +0000

Hi everyone,
 It seems that my question is of interest to many people, though I got
 only two serious replys. The bottom line from those answers is not to
 expect too much. It might work for a shared memory SMP machine, but it
 is not particulary good for distributed memory machines. Attached is my
 original question and the replys.
 Silviu.
 -------- Original Message --------
 Hi everyone,
 Does anyone has experience with using auotmatic parallelization tools,
 for old Fortran and C codes?
 We are buying a PC cluster, and I look for a quick and dirty way of
 getting parallel codes out of seriel one.
 Thanks,
 Silviu Zilberman.
 --
 Subject:
            Re: CCL:automatic parallelization
       Date:
            29 Nov 2001 17:36:42 +0100
       From:
            Konrad Hinsen <hinsen # - at - # cnrs-orleans.fr>
         To:
            Zilberman Silviu <silviu # - at - # post.tau.ac.il>
  References:
            1
 Zilberman Silviu <silviu # - at - # post.tau.ac.il> writes:
 > Does anyone has experience with using auotmatic parallelization tools,
 > for old Fortran and C codes?
 > We are buying a PC cluster, and I look for a quick and dirty way of
 > getting parallel codes out of seriel one.
 Don't expect much from them. Automatic parallelization for SMP
 machines works well for some codes, but certainly not for all. And I
 haven't even seen a production compiler that pretends to do automatic
 parallelization for distributed memory machines such as a PC cluster.
 If you get biprocessor nodes, you might have some success. Just try
 the new Intel compilers for Linux with the free evaluation licence!
 --
 Subject:
            Re: CCL:automatic parallelization
       Date:
            Thu, 29 Nov 2001 17:34:39 +0000
       From:
            Maurice Cafiero <mcafiero # - at - # u.arizona.edu>
         To:
            Zilberman Silviu <silviu # - at - # post.tau.ac.il>
         CC:
            ccl <chemistry # - at - # ccl.net>
  References:
            1
 hello:
     I have used the automatic parallelization tools that come with SGI
 Fortan, and they
 are pretty terrible. They created a 2/3% speedup and were about 5%
 parallel.
     I suggest 2 things:
     1) Use parallel numerical libraries. These are pre-existing and can
 probably be downloaded
           from netlib.
     2) Learning basic MPI is not difficult at all for an experienced
 FORTRAN programmer.
           I learned it in about 3 weeks and my code is 80/90% parallel.
 I get excellent speedup
           (approximately linear with # procs).
 What type of program are you trying to parallelize?
 --
 Mauricio Cafiero
 Doctoral Candidate : Theoretical
                      and Computational
                      Quantum Chemistry
 Department of Chemistry
 University of Arizona

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