[CPMD-list] CPMD parallel scalability

[Maurice de Koning]

Hi all,

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

Cheers,

Maurice

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

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

&DFT
FUNCTIONAL BLYP
&END