Hybrid programming with MPI & OpenMP - Prace Training Portal

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Performance of the 3DFFT in QEBCX – CINECAFFT: Speed‐up, relative to 64 cores Pure MPI5 Pure MPIMPI+OpenMP, 4 threads4 MPI+OpenMP, 2 threads321064 128 256 512 1024coresHPCx - EPCCFFT: Speed‐up, relative to 64 cores Pure MPI8PURE MPI7MPI+OpenMP, 4 threads6MPI+OpenMP, 2 threads5MPI+OpenMP, 8 threads43210 64 128 256 512 1024coresFFT GRID size: 200 200 20016Task Groups28
Space Integrals: Electrostatic potentialsimple loop parallelization!$omp parallel do default(shared), private(rp,is,rhet,rhog,fpibg), p, , , p g), reduction(+:eh,ehte,ehti), DO ig = gstart, ngmrp = (0.D0,0.D0)DO is = 1, nsprp = rp + sfac( ig, is ) * rhops( ig, is ) Ionic density (reciprocal space)END DOrhet = rhoeg( ig )Electronic density (reciprocal space)rhog = rhet + rpIF( tscreen ) THENfpibg = fpi / ( g(ig) * tpiba2 ) + screen_coul(ig)ELSEfpibg = fpi / ( g(ig) * tpiba2 )END IFHartree potentialvloc(ig) = vloc(ig) + fpibg * rhogHatree Energyeh = eh + fpibg * rhog * CONJG(rhog)ehte = ehte + fpibg * DBLE(rhet * CONJG(rhet))ehti = ehti + fpibg * DBLE( rp * CONJG(rp))END DOIonic contributionElectronic contribution! IBM xlf compiler does not like name of function used for OpenMP reduction29
Page 1 and 2: workshop on application porting and
Page 3 and 4: Motivation:Paradigm Change in HPC30
Page 5 and 6: Standard de-factoMPI (inter node)Op
Page 7 and 8: Mixed Paradigm• PROS:- Better use
Page 10 and 11: Ab-initio simulations:The “standa
Page 12: Parallelization (before OpenMP)1x1x
Page 15 and 16: HECToR - PSIWAT (DEISA benchmark)Pe
Page 17 and 18: Parallelization Strategy• 3D FFT
Page 19 and 20: Changing architecture: HPCxHPCx - W
Page 21 and 22: Multithread libraries (mkl, acml, e
Page 23 and 24: Understanding QE 3DFFT, Paralleliza
Page 25 and 26: Understanding QE 3DFFT: master-only
Page 27: QE 3DFFT: multiple • Pros:- Overl
Page 31 and 32: Point Function evaluation:Exchange
Page 33 and 34: pDO nt = 1, ntypIF ( upf(nt)%tvanp
Page 35 and 36: PDSYEVX vs ad-hoc subroutineTurboRV
Page 37 and 38: Conclusion• Number of cores doubl

Hybrid programming with MPI & OpenMP - Prace Training Portal

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