Scaling of a Fast Fourier Transform and a pseudo-spectral fluid solver up to 196608 cores

Anando G. Chatterjee, Mahendra K. Verma, Abhishek Kumar, Ravi Samtaney, Bilel Hadri, Rooh Khurram

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    In this paper we present scaling results of a FFT library, FFTK, and a pseudospectral code, Tarang, on grid resolutions up to 81923grid using 65536 cores of Blue Gene/P and 196608 cores of Cray XC40 supercomputers. We observe that communication dominates computation, more so on the Cray XC40. The computation time scales as Tcomp∼p−1, and the communication time as Tcomm∼n−γ2with γ2ranging from 0.7 to 0.9 for Blue Gene/P, and from 0.43 to 0.73 for Cray XC40. FFTK, and the fluid and convection solvers of Tarang exhibit weak as well as strong scaling nearly up to 196608 cores of Cray XC40. We perform a comparative study of the performance on the Blue Gene/P and Cray XC40 clusters.
    Original languageEnglish
    Pages (from-to)77-91
    Number of pages15
    JournalJournal of Parallel and Distributed Computing
    Early online date3 Nov 2017
    Publication statusPublished - 1 Mar 2018



    • Extreme-resolution turbulence simulation
    • Fast Fourier transform
    • Pseudospectral method
    • Turbulence simulation

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