XANSYS Message: 265 [Go back to message list]
[bookmark on del.icio.us]
No rating yet
Rate item:

Subject: Re: ANSYS and parallel processing...
Author: John Swanson
Date: 1999-01-15 14:57:00

ANSYS parallel processing improves with each release. In 5.5 I would
recommend using up to 3 processors on a 4 processor machine. You should
see at least a factor of 2 improvement.
However, there are areas where parallel is not supported, such as
the
Sparse Matrix solvers (Static or Eigenvalue).
There are other places where the process is memory bandwidth
limited,
so the improvement is not as much as we would like. The major one of
these is the iterative solvers. An improvement of 50% is good, unless
you
have a machine with a crossbar memory system (high end SGI, Cray), where
2.5 to 3 is possible.
For moderate size non-linear problems where the element time is
a major part of the total process you should see good speed-up.
John.Swanson

> -----Original Message-----
> From: Viktor Doundakov [SMTP:Viktor.Doundakov@R...]
> Sent: Friday, January 15, 1999 2:52 PM
> To: 'xansys@o...'
> Subject: [xansys] ANSYS and parallel processing...

> From: Viktor Doundakov

> Hi Joseph,

> I've heard that the ANSYS parallel processing is not very good (and in
> general I am told that it holds for the FEA since you work on
> matrixes). I
> have a dual Pentium II processor PC and if I am wrong on the subject
> and I
> can take advantage of parallel processing it will help me a lot since
> I am
> starting to run relatively big jobs.

> Anybody with info on the subject will help.

> Viktor Doundakov
> R&D Engineer
> Read-Rite Corporation
> Direct: 510-683-7495 Main: 510-683-6100 FAX: 510-683-7065
> e-mail: Viktor.Doundakov@r...

> -----Original Message-----
> From: Metrisin, Joseph T. [mailto:metrisin@p...]
> Sent: Friday, January 15, 1999 9:34 AM
> To: 'xansys@o...'
> Subject: [xansys] Re: Multiple CPU's in SUN environment

> From: "Metrisin, Joseph T."

> Geno,

> If you are looking at the CPU time printed at the bottom of the
> ANSYS output, this is the TOTAL CPU time accumulated by
> all four processors. In other words, your job still takes nearly
> the same amout of CPU time to solve, it's just spread out over
> the various processors. If you look at the elapsed time, it
> will probably show that it solved in roughly 1/4 of the wall clock
> time.

> Joseph T. Metrisin

> Structural Methods
> Pratt & Whitney/Unitetd Technologies
> M/S: 714-03
> P.O. Box 109600
> West Palm Beach, FL. 33410-9600

> Phone: (561) 796-5967
> Fax: (561) 796-8993

> > From: Geno Vallejos[SMTP:gvalle@c...]
> > Sent: Friday, January 15, 1999 12:01 PM
> > To: xansys@o...
> > Subject: [xansys] Multiple CPU's in SUN environment

> > From: Geno Vallejos

> > To all my fellow ANSYS users:

> > I have had some interesting results when solving the same structural
> > problem using the same model but on two different SUN machines.
> > Below are the specifics;

> > The structural model is a part created in ProENGINEER 18
> > I am using ANSYS ProFEA 5.4 and ProENGINEER 18.

> > Solution #1:
> > Machine: SUN E-3000 server
> > Processors: 4 each 360 MHz CPU's
> > Operating System: Solaris 2.6
> > CP Time (from the file.lst summary) = 10 minutes 28 seconds

> > The first time I requested four CPU's using the config.ans file,
> with the
> > following line added;
> > NUM_PROC = 4
> > The config.ans file was located in the /docu directory.
> > The file.lst indicated that 4 CPU's will be used

> > The second time I requested four CPU's using a .inp file. The .inp
> file
> > had
> > the following line;
> > /config,nproc,4

> > The solution times (CP Time listed above) was 10 minutes 28 seconds

> > Solution #2:
> > Machine: SUN Ultra 60 workstation
> > Processors: 1 each 360 MHz CPU
> > Operating System: Solaris 2.6
> > CP Time (from the file.lst summary) = 10 minutes 53 seconds

> > Can anyone help explain why the E-3000 server and the Ultra 60
> > workstation solved the structural analysis problem by taking the
> same
> > amount of time????

> > I have heard some ideas....but nothing concrete. Some here at ATL
> say
> > that the four SUN processors will work as hard as they need to to
> solve
> > the problem. I say that I would like them to solve the problem as
> fast as
> > possible. Observing the CPU activity bar during the solution phase
> > indicated that at no time were any of the four CPU's working any
> higher
> > than 40-50% of maximum capacity. Was this due to some SUN or
> Solaris
> > setting "chocking" the CPU speed or efficiency; or some ANSYS
> setting
> > not getting the full support of multi-tasking from the SUN server??

> > Thanks in advance!

> > Geno Vallejos
> > ATL Ultrasound - A Philips Company
> > Bothell, Washington 98021
> > www.atl.com

Posts possibly associated with message #265AuthorDateScore
263ANSYS and parallel processing...Viktor Doundakov1999/01/15 
265Re: ANSYS and parallel processing...John Swanson1999/01/15 
267Re: ANSYS and parallel processing...Brian Breaux1999/01/15 
268Re: ANSYS and parallel processing...Brian Murphy1999/01/15 
271Re: ANSYS and parallel processing...Joe Metrisin1999/01/15 
273Re: ANSYS and parallel processing...Viktor Doundakov1999/01/15 
275Re: ANSYS and parallel processing...Brian Breaux1999/01/15 
278Re: ANSYS and parallel processing...John Swanson1999/01/15 
286Re: ANSYS and parallel processing...Terje Fredriksen1999/01/18