[CP2K:4198] About the OPENMP+MPI issue of CP2k

[Urban Borštnik]

Hi,

The hybrid (OpenMP + MPI) code is generally most useful for HFX and
scale-out (using a lot of cores for relatively small sysetms).  In other
cases you will probably get faster runs using pure MPI.

Otherwise, at least
* try to use thread affinity or
* use the machine architecture support (hwloc or libnuma).

Regards,
Urban.

On Sun, 2012-11-18 at 18:54 -0800, jjf_... at yahoo.com.cn wrote:
> Hi, everyone,
> 
> I have successfully compiled the cp2k in openmp+mpi. When I start the
> cp2k by following mpirun command, I find the times for every SCF step
> are different remarkablly, and also find that the CPU usage on the
> computing node are not always 800%(There are two 4-core CPU on each
> node).  Does anyone have idea about it or have any experience to
> promote the paralleling efficiency. 
> 
> The command:
> 
> /opt/mvapich2-1.8.1/bin/mpirun_rsh -ssh -hostfile nodes.$$ -np 10
> MV2_ENABLE_AFFINITY=0  OMP_NUM_THREADS=8 cp2k.psmp TiO2.inp >TiO2.out
> 
> (I have 10 nodes in the nodesfile)
> 
> The OUT PUT for SCF:
> 
>  ----------------------------------- OT
> ---------------------------------------
> 
>  Step     Update method      Time    Convergence         Total energy
> Change
>  ------------------------------------------------------------------------------
>     1 OT DIIS     0.15E+00   78.8     0.00489573    -11358.8478798550
> -1.14E+04
>     2 OT DIIS     0.15E+00   49.5     0.00418778    -11408.3162227805
> -4.95E+01
>     3 OT DIIS     0.15E+00   74.5     0.00337817    -11430.9534193832
> -2.26E+01
>     4 OT DIIS     0.15E+00   48.2     0.00386960    -11458.1345581625
> -2.72E+01
>     5 OT DIIS     0.15E+00   47.1     0.00203908    -11483.8037596735
> -2.57E+01
>     6 OT DIIS     0.15E+00   63.8     0.00156578    -11514.2831610125
> -3.05E+01
>     7 OT DIIS     0.15E+00   66.8     0.00114899    -11541.2744732691
> -2.70E+01
>     8 OT DIIS     0.15E+00   47.8     0.00088405    -11557.1215180177
> -1.58E+01
>     9 OT DIIS     0.15E+00   62.4     0.00074951    -11566.0261626878
> -8.90E+00
>    10 OT DIIS     0.15E+00   69.6     0.00063936    -11573.9602882755
> -7.93E+00
>    75 OT DIIS     0.15E+00   85.0     0.00001131    -11617.3170395951
> -8.91E-03
>    90 OT DIIS     0.15E+00   45.1     0.00000688    -11617.3824121651
> -1.08E-03
> 
> 
> Best wishes
> 
> Jianfeng
> 
> 
> 
> 
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