[QE-users] mutlicore usage for GPU.

[Paolo Giannozzi]

On 26/04/2024 23:00, Bhargab Kakati wrote:

> while using more 
> than one core (mpirun -np 8) the calculation becomes very slow but it is 
> way faster when I do "mpirun -np 1". Is there a reason for that?

of course there is a reason, and you mention it in the following line:

> I have only 1 GPU

You should run one MPI process per GPU. If you have 1 GPU, you don't 
even need MPI. You may find OpenMP useful if you have available CPU 
cores, but don't expect any serious speedup from OpenMP

Paolo
-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
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