[DFTB-Plus-User] Problems with DFTB Stable version 19.1

[Ben Hourahine]

Hello Junmian,

9 processes for such a small structure is probably spin-locking, as it
will try and spread the diagonalisation across the 9 processors and work
through the k-points 1 at a time. Hence any network lag or congestion
will hit the performance of this very strongly.

What happens if you add this extra block to the input:

Parallel {
  Groups = 8
}

and run with

mpirun -np 8 dftb+

?

This setting will run batches of 8 k-points at a time (you have 64 in
total).

Regards

Ben

On 05/07/2019 22:44, Zhu, Junmian wrote:
>
> Dear DFTB+ Community,
>
>  
>
> I have experienced problems with MPI-enabled DFTB+ geometric
> optimization calculation (version: 19.1 stable release), and am able
> to reproduce the problem. When running the command “mpirun -np 9
> dftb+” with the given input file, DFTB+ always stops at geometric step
> 59. Even though the DFTB+ process is still running at the backend as
> shown by “top” command, it stops streaming any output and got stuck
> there for more than 12 hours.  
>
>  
>
> The behavior of DFTB+ is quite strange, because DFTB+ is able to
> continue to run and finish the calculation if the process is killed
> and restarted again, using the previous output geometry and charges.
> Multiple tests on the same computer give exactly the same output and
> get stuck exactly at step 59. (Changing number of processors only
> changes the step it got stuck, and OpenMP is disabled.)Therefore, I
> suspect this is an issue with the DFTB+ software and would like to
> request help on solving this problem.
>
>  
>
> Thank you very much,
>
>  
>
> Junmian Zhu
>
> University of California, Berkeley
>
>  
>
>  
>
>
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-- 
        Dr.  B.  Hourahine,  Senior  lecturer
            SUPA, Department  of  Physics,
             University  of  Strathclyde,
              John  Anderson  Building,
          107 Rottenrow, Glasgow G4 0NG, UK.                    
  +44 141 548 2325, benjamin.hourahine at strath.ac.uk

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       registered in Scotland, number SC015263

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