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>
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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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