Dear Quantum Espresso Experts, I've been running a phonon calculation using QE-7.2 on both CPU and GPU and have noticed significantly different runtimes in the preparation step. I'd appreciate insights on how to improve the GPU performance.
CPU Setup: Nodes: 8 Cores per Node: 128 Parallelization: 8 images, 4 npools (calculation has 4 k-points) GPU Setup: Nodes: 8 GPUs per Node: 4 OMP_NUM_THREADS: 1 Parallelization: 8 images, 4 npools (calculation has 4 k-points) The preparation step, including steps like "Compute atoms," "Ewald sum," and charge density calculations, took around 9 hours on the CPU setup but over 24 hours on the GPU setup. Below is a section from the CPU calculation output before computing scf of each representation mode: ---------------------------------------------------------------- Compute atoms: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, Alpha used in Ewald sum = 2.8000 negative rho (up, down): 9.781E-01 0.000E+00 PHONON : 8h51m CPU 8h56m WALL Representation # 1 mode # 1 Self-consistent Calculation ----------------------------------------------------------------------- Why might the preparation step for the GPU-based calculation be taking significantly longer? Are there specific optimizations or configurations I can apply to improve GPU performance in QE phonon calculations? Thank you in advance for your help! Best regards, PhD student in Forschungszentrum Jülich Yin-Ying Ting -- Forschungszentrum Jülich GmbH Institute of Energy and Climate Research Theory and Computation of Energy Materials (IEK-13) E-mail: y.t...@fz-juelich.de<mailto:y.t...@fz-juelich.de> ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Jülich GmbH 52425 Jülich Sitz der Gesellschaft: Jülich Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Stefan Müller Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende), Karsten Beneke (stellv. Vorsitzender), Dr. Ir. Pieter Jansens ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------
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