[CPMD-list] CPMD parallel scalability

[Alexandr Isayev]

Dear Maurice,

In addition to other suggestions...

I'm not sure about Altix 4700, however on our Altix 3700
there is a "dplace" utility from SGI ProPack that can possibly
improve scalability (assuming no hardware/software problems :)
of your job under heavily loaded machine.

it should be run something like:

mpirun -np $NCPUS dplace -c1-$NCPUS -s1 <your app is here>

Greetings from Jackson,
Alexandr



Monday, April 14, 2008, 8:57:43 AM, you wrote:

MdK> Hi all,

MdK> I´m running CPMD on an Altix 4700 system with 44 CPU´s and 88 Gb of RAM
MdK> memory.
MdK> At the moment I´m running a CP MD run of a cell containing 96 water 
MdK> molecules using the
MdK> BLYP functional at 300 K. I noticed that the scalability is not very 
MdK> good. If I run on more than
MdK> about 16 CPU´s, the time per MD step starts even increases, such that 
MdK> the total time starts growing with the
MdK> number of CPU´s. Is there anything I can do about this?
MdK> Below is a part of the input script

MdK> Cheers,

MdK> Maurice

MdK> &CPMD
MdK>   MOLECULAR DYNAMICS CP
MdK>   RESTART WAVEFUNCTION COORDINATES VELOCITIES
MdK>   QUENCH BO ELECTRONS
MdK>   TIMESTEP
MdK>   4
MdK>   TEMPCONTROL IONS
MdK>   300.0 40
MdK>   MAXSTEP
MdK>   20000
MdK>   TRAJECTORY XYZ
MdK>   EMASS
MdK>   600
MdK>   STORE
MdK>   100
MdK> &END

MdK> &SYSTEM
MdK>   SYMMETRY
MdK>   8
MdK>   SCALE
MdK>   ANGSTROM
MdK>   CELL ABSOLUTE
MdK>   13.1493536801862057 15.1976493759670106 14.3247149284289197 0 0 0
MdK>   CUTOFF
MdK>   70
MdK> &END

MdK> &DFT
MdK> FUNCTIONAL BLYP
MdK> &END

MdK> _______________________________________________
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MdK> CPMD-list at cpmd.org
MdK> http://cpmd.org/mailman/listinfo/cpmd-list



-------------------------------------------------------
Alexandr Isayev,
Graduate Research Assistant, and System Administrator
@ Computational Center for Molecular Structure
and Interactions (CCMSI),
Jackson State University,
Jackson, MS USA
   Tel:  +(601) 979-1134
e-mail:  alex(at)ccmsi.us
   Web:  http://www.ccmsi.us/alex
--------------------------------------------------------