Enabling the UCD-SPH code on the Xeon Phi

Christian Lalanne (1) , Ashkan Rafiee (2, 3) , Denys Dutykh (3, 4) , Michael Lysaght (5) , Frédéric Dias (3)

1 ICHEC - Irish Centre for High-End Computing
2 Carnegie Wave Energy Ltd
3 School of Mathematical Sciences [Dublin]
4 LAMA - Laboratoire de Mathématiques
5 ICHEC - Irish Centre for High-End Computing

This white-paper reports on our efforts to enable an SPH-based Fortran code on the Intel Xeon Phi. As a result of the work described here , the two most computationally intensive subroutines (rates and shepard_beta) of the UCD-SPH code were refactored and parallelised with OpenMP for the first time, enabling the code to be executed on multi-core and many-core shared memory systems. This parallelisation achieved speedups of up to 4.3x for the rates subroutine and 6.0x for the shepard_beta subroutine resulting in overall speedups of up to 4.2x on a 2 processor Sandy Bridge Xeon E5 machine. The code was subsequently enabled and refactored to execute in different modes on the Intel Xeon Phi co-processor achieving speedups of up to 2.8x for the rates subroutine and up to 3.8x for the shepard_beta subroutine producing overall speedups of up to 2.7x compared to the original unoptimised code. To explore the capabilities of auto-vectorisation the shepard_beta subroutine was refactored which results in speedups of up to 6.4x for the shepard_beta subroutine relative to the original unoptimised version of the shepard_beta subroutine. The development and testing phases of the project were carried out on the PRACE EURORA machine.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]; Analyse numérique [cs.NA]; Calcul parallèle, distribué et partagé [cs.DC]; Physique Numérique [physics.comp-ph]; Analyse numérique [math.NA]; Dynamique des Fluides [physics.flu-dyn]

Christian Lalanne, Ashkan Rafiee, Denys Dutykh, Michael Lysaght, Frédéric Dias. Enabling the UCD-SPH code on the Xeon Phi. 2014. ⟨hal-00927227v2⟩