[QE-users] [QE-GPU] computing force and stress - time cost

[Pietro Bonfa']

Dear Mohammad,

the performance of the GPU code depends dramatically on the portions of 
computation that are still performed on the CPU. Only a portion of all 
contributions to forces have been accelerated, and what is left out may 
be optimized for MPI parallelism rather than openmp.

That being said, the behavior that you report is definitively unusual. 
Would you mind sharing input and output files?

Best regards,
Pietro



On 1/3/21 8:52 AM, Mohammad Moaddeli wrote:
> Dear all,
> 
> GPU enabled QE v.6.7 is compiled on a VOLTA card. I am trying to run a 
> vc-relax for a bulk containing 48 atoms. Although diagonalization 
> (davidson) is about 3x faster than CPU, it takes a lot of time (a couple 
> of hours) to compute force and stress. Is this something related to the 
> code itself?
> 
> Best,
> 
> Mohammad Moaddeli
> ShirazU
> 
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