[Pw_forum] why my pw.x run with low efficiency?

[vega]

Dear all,

I just finished a relax calculation for 120 atoms. After calculation was done, the outputfile reported as follows,

    Program PWSCF     v.4.0.1  starts ...
     Today is 16Sep2008 at 19:14:42 

     Parallel version (MPI)

     Number of processors in use:      78
     K-points division:     npool     =    3
     R & G space division:  proc/pool =   26

     For Norm-Conserving or Ultrasoft (Vanderbilt) Pseudopotentials or PAW
................................
     per-process dynamical memory:   129.6 Mb
................................

     PWSCF        :     0d   14h46m CPU time,        2d   18h 4m wall time

     init_run     :    91.49s CPU
     electrons    : 47137.56s CPU (      27 calls,1745.836 s avg)
     update_pot   :   187.80s CPU (      26 calls,   7.223 s avg)
     forces       :  4492.20s CPU (      27 calls, 166.378 s avg)

     Called by init_run:
     wfcinit      :    23.68s CPU
     potinit      :     3.15s CPU

     Called by electrons:
     c_bands      : 23198.29s CPU (     258 calls,  89.916 s avg)
     sum_band     : 11159.67s CPU (     258 calls,  43.255 s avg)
     v_of_rho     :   167.39s CPU (     280 calls,   0.598 s avg)
     newd         : 13679.79s CPU (     280 calls,  48.856 s avg)
     mix_rho      :    30.14s CPU (     258 calls,   0.117 s avg)

     Called by c_bands:
     init_us_2    :    48.95s CPU (     517 calls,   0.095 s avg)
     cegterg      : 23038.94s CPU (     258 calls,  89.298 s avg)

     Called by *egterg:
     h_psi        :  8629.82s CPU (    1459 calls,   5.915 s avg)
     s_psi        :  2230.78s CPU (    1459 calls,   1.529 s avg)
     g_psi        :    34.68s CPU (    1200 calls,   0.029 s avg)
     cdiaghg      :  5929.74s CPU (    1427 calls,   4.155 s avg)

     Called by h_psi:
     add_vuspsi   :  2209.17s CPU (    1459 calls,   1.514 s avg)

     General routines
     calbec       :  2904.12s CPU (    1744 calls,   1.665 s avg)
     cft3s        :  4337.89s CPU (  950068 calls,   0.005 s avg)
     interpolate  :    34.87s CPU (     538 calls,   0.065 s avg)
 
     Parallel routines
     fft_scatter  :   538.83s CPU (  950068 calls,   0.001 s avg)