[CPMD-list] how to speed up on amd64 machines

[Bin Pan]

Hi Prof. Hutter,

I said that it is very slow because I used 6 CPU's on a Dual Core AMD 
Opteron(tm) Processor 870 connected by myrinet and compared the
time required to finish one MD cycle with that done by 4 CPU's on a 
Intel(R) Xeon(TM) CPU 3.00GHz connected by ethernet for the same system.
The first needs ~90 seconds, however the second only needs ~60.
I expected the first one has faster CPU and better network connection.

Are these enough info for you to give me some advice in how to 
improve the speed?
Thanks a lot!

Best regards,
Bin.

At 02:57 4/16/2007, Juerg Hutter wrote:
>Hi
>
>you have to give us more precise information.
>What exactly do you mean by 'it is very slow'.
>Do you mean slow in general, e.g. compared to
>another plane wave code or slow because
>of bad speedups in parallel compared to the
>serial runs?
>You should also give us some information on your
>computer. What is the exact version of your CPUs
>and what is the type of your network?
>At the end of each run CPMD prints timing information.
>Please attach at least one such timing information
>block for a run that you consider too slow.
>
>regards
>
>Juerg Hutter
>
>----------------------------------------------------------
>Juerg Hutter                   Phone : ++41 44 635 4491
>Physical Chemistry Institute   FAX   : ++41 44 635 6838
>University of Zurich           E-mail: hutter at pci.unizh.ch
>Winterthurerstrasse 190
>CH-8057 Zurich, Switzerland
>----------------------------------------------------------
>
>
>On Sun, 15 Apr 2007, Bin Pan wrote:
>
>>Hi CPMD users,
>>
>>I am wondering how to speed up CPMD runs on amd64 cluster using MPI
>>parallelization.
>>Previously I compiled CPMD using pgi compiler with acml. However, I
>>found it is very slow.
>>The flags I used are:
>>
>>CPPFLAGS = -P -C -traditional -D__Linux -D__PGI -DFFT_DEFAULT
>>-DPOINTER8 -D__pgf90 -DPARALLEL -DMYRINET
>>CC = gcc -O2 -Wall -m64
>>FC = pgf90 -c -fastsse -tp k8-64
>>LD = pgf90 -fastsse -tp k8-64
>>
>>Can you please let me know how to improve the performance?
>>Thanks a lot!
>>
>>Best regards,
>>Bin.
>>
>>_______________________________________________
>>CPMD-list mailing list
>>CPMD-list at cpmd.org
>>http://cpmd.org/mailman/listinfo/cpmd-list



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Bin Pan
Ph.D. Candidate
Department of Chemical Engineering
Massachusetts Institute of Technology
Tel: 617-253-6675
E-mail: binpan at mit.edu
Room E19-528, 77 Mass. Ave. Cambridge, MA
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