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Subject: Re: Multiple CPUs in SUN environment
Author: Heinz.Hempowitz@
Date: 1999-01-15 15:18:00

Hi Geno, ANSYS users,

we had the same experience with ANSYS 5.4 on SUN.
Even with OS 2.6, it seems, that the SUN was using 4 processors, but the
real WALL CLOCK TIME showed a incredible bad performance on the SUN. All
processors used, but no real time win.

During the LS-DYNA conference 1998 we met SUN and they admit a problem with
the E-3000 Server on all OS up til 2.6.
On some machines it worked, on some not. We had also some Tests on similar
machines with some better results (real parallelisation). No idea why it
was so unpredictable.

best regards

Heinz.

PS: As a hint:
If you use the Double Proc. Pentium II with Xeon Processors (we tried it),
you will see a relatively good parallel performance with ANSYS (even with
5.4). This was measured with several different benchmarks between 3000 and
30000 elements.
If you like to calculate with only one processor, you should fix the
process on ONE specific processor.
Windows NT plays table tennis with the job if you use 1 proc and no other
big job is running on the machine.
This is caused by the process/usage analysation programm in NT. If one proc
is fully used, the other one free and both switched ON for ANSYS, it will
move the job from one proc to the other. Forth and Back (endless).
If you use the TASK MANAGER, you can freeze the process to one processor
(results in a much higher performance).

Xeon Benchmarks with ANSYS are published on the Hewlett Packard Internet
page (try search for XEON BENCHMARK ANSYS). MARC has published parallel
performance on Double processor Pentium II MPI-Systems (coupled direct via
ETHERNET compared to a 4 proc. Pentium II system).
Interesting strategy.

To: xansys@o...
cc: (bcc: Heinz Hempowitz/NHT/Hydro)

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 #270AuthorDateScore
247Multiple CPUs in SUN environmentGeno Vallejos gvalle@1999/01/15 
248Re: Multiple CPUs in SUN environmentBrian Breaux1999/01/15 
250Re: Multiple CPUs in SUN environmentJoe Metrisin1999/01/15 
260Re: Multiple CPUs in SUN environmentBrian Murphy1999/01/15 
266Re: Multiple CPUs in SUN environmentJohn Swanson1999/01/15 
269Re: Multiple CPUs in SUN environmentPatrick Tibbits1999/01/15 
270Re: Multiple CPUs in SUN environmentHeinz.Hempowitz@1999/01/15 
281Re: Multiple CPUs in SUN environmentDan Bohlen1999/01/16 
283Re: Multiple CPUs in SUN environmentJohn Swanson1999/01/16 
323Summary of Multiple CPUs in SUN environment questionGeno Vallejos gvalle@1999/01/19 
324Re: Summary of Multiple CPUs in SUN environment queChristopher Wright1970/01/01 
332Re: Summary of Multiple CPUs in SUN environment questionJoe Rasche1999/01/20 
340Re: Summary of Multiple CPUs in SUN environment questionBrian Murphy1999/01/20