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-   -   Help with parallel exec on Intel i7 (http://www.cfd-online.com/Forums/star-ccm/82411-help-parallel-exec-intel-i7.html)

cfdnewbie1 November 25, 2010 09:35

Help with parallel exec on Intel i7
 
Hello to everybody,

I'm a complete newbie with CFD and Star-CCM+.
I'm trying to learn something on this software thru tutorials and examples.

I have the following problem: when I start Star-CCM+ in parallel mode I get the following warning:

Starting local server: starccm+ -server -np 2
Worker Node[2]@XXXX process 692 (MPICH2:nemesis)
Master Node[0]@XXXX process 5460 (MPICH2:nemesis)

STAR-CCM+ Version 4.04.011 (win64/intel10.1)
Worker Node[1]@XXXX process 5404 (MPICH2:nemesis)

Server::start XXXX:51786
Disabling parallel asynchronous communications.
STAR-CCM+ will avoid using non-blocking communication. This may degrade the performance.


My machine is a laptop with a intel-i7 Q720 (4 core - 8 threads), I use Windows 7 64 bit, and MPICH2 ver. 1.3.

My question is: is there a way to configure MPICH2 or Star to use the parallel asynchronous comms? How much does this have an impact on performance?

Thank you very much for your help.

Regards

f-w November 29, 2010 15:25

It has a small but measurable effect. There's a checkbox in Tools>Options>Parallel> that you can change.

cfdnewbie1 November 29, 2010 15:55

thank you very much! i will do some benchmarks.

fastwave December 1, 2010 09:58

What are the disadvantages of using the asynchronous?

cfdnewbie1, I would be interested on the bechmark times. If you can pst them when done that would be appreciated.

fw

cfdnewbie1 December 23, 2010 08:27

Here the results of the benchmark done with the bluntbody.sim tutorial.
4 cpus

Enabled
Solution
Accumulated CPU Time over all processes (s) 6007.063
Elapsed Time (s) 1506.699829
Iterations 1500

Disabled
Solution
Accumulated CPU Time over all processes (s) 6178.668
Elapsed Time (s) 1550.230431
Iterations 1500

filippo.aero December 25, 2010 05:34

hello, just a simple information: I'm trying to do the same on an i7, but star-ccm replies with "no MPI distribution found", even if I installed mpich2. How did you get it to work? I mean, first installed star, then mpich, etcc

cfdnewbie1 December 27, 2010 11:07

You have to start the set the mpich process to start automatically.

try to google
smpd.exe –install
mpiexec.exe –register
you can find all the info!

Hi


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