1 #include <petscvec_kokkos.hpp> 2 #include <../src/vec/vec/impls/seq/kokkos/veckokkosimpl.hpp> 3 #include <petscdevice.h> 4 #include <../src/ksp/pc/impls/pbjacobi/pbjacobi.h> 5 6 struct PC_PBJacobi_Kokkos { 7 PetscScalarKokkosDualView diag_dual; 8 9 PC_PBJacobi_Kokkos(PetscInt len, PetscScalar *diag_ptr_h) 10 { 11 PetscScalarKokkosViewHost diag_h(diag_ptr_h, len); 12 auto diag_d = Kokkos::create_mirror_view_and_copy(DefaultMemorySpace(), diag_h); 13 diag_dual = PetscScalarKokkosDualView(diag_d, diag_h); 14 } 15 16 PetscErrorCode Update(const PetscScalar *diag_ptr_h) 17 { 18 PetscFunctionBegin; 19 PetscCheck(diag_dual.view_host().data() == diag_ptr_h, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Host pointer has changed since last call"); 20 PetscCallCXX(diag_dual.modify_host()); /* mark the host has newer data */ 21 PetscCallCXX(diag_dual.sync_device()); 22 PetscFunctionReturn(PETSC_SUCCESS); 23 } 24 }; 25 26 /* Make 'transpose' a template parameter instead of a function input parameter, so that 27 it will be a const in template instantiation and gets optimized out. 28 */ 29 template <PetscBool transpose> 30 static PetscErrorCode PCApplyOrTranspose_PBJacobi_Kokkos(PC pc, Vec x, Vec y) 31 { 32 PC_PBJacobi *jac = (PC_PBJacobi *)pc->data; 33 PC_PBJacobi_Kokkos *pckok = static_cast<PC_PBJacobi_Kokkos *>(jac->spptr); 34 ConstPetscScalarKokkosView xv; 35 PetscScalarKokkosView yv; 36 PetscScalarKokkosView Av = pckok->diag_dual.view_device(); 37 const PetscInt bs = jac->bs, mbs = jac->mbs, bs2 = bs * bs; 38 const char *label = transpose ? "PCApplyTranspose_PBJacobi_Kokkos" : "PCApply_PBJacobi_Kokkos"; 39 40 PetscFunctionBegin; 41 PetscCall(PetscLogGpuTimeBegin()); 42 VecErrorIfNotKokkos(x); 43 VecErrorIfNotKokkos(y); 44 PetscCall(VecGetKokkosView(x, &xv)); 45 PetscCall(VecGetKokkosViewWrite(y, &yv)); 46 PetscCallCXX(Kokkos::parallel_for( 47 label, bs * mbs, KOKKOS_LAMBDA(PetscInt row) { 48 const PetscScalar *Ap, *xp; 49 PetscScalar *yp; 50 PetscInt i, j, k; 51 52 k = row / bs; /* k-th block */ 53 i = row % bs; /* this thread deals with i-th row of the block */ 54 Ap = &Av(bs2 * k + i * (transpose ? bs : 1)); /* Ap points to the first entry of i-th row */ 55 xp = &xv(bs * k); 56 yp = &yv(bs * k); 57 /* multiply i-th row (column) with x */ 58 yp[i] = 0.0; 59 for (j = 0; j < bs; j++) { 60 yp[i] += Ap[0] * xp[j]; 61 Ap += (transpose ? 1 : bs); /* block is in column major order */ 62 } 63 })); 64 PetscCall(VecRestoreKokkosView(x, &xv)); 65 PetscCall(VecRestoreKokkosViewWrite(y, &yv)); 66 PetscCall(PetscLogGpuFlops(bs * bs * mbs * 2)); /* FMA on entries in all blocks */ 67 PetscCall(PetscLogGpuTimeEnd()); 68 PetscFunctionReturn(PETSC_SUCCESS); 69 } 70 71 static PetscErrorCode PCDestroy_PBJacobi_Kokkos(PC pc) 72 { 73 PC_PBJacobi *jac = (PC_PBJacobi *)pc->data; 74 75 PetscFunctionBegin; 76 PetscCallCXX(delete static_cast<PC_PBJacobi_Kokkos *>(jac->spptr)); 77 PetscCall(PCDestroy_PBJacobi(pc)); 78 PetscFunctionReturn(PETSC_SUCCESS); 79 } 80 81 PETSC_INTERN PetscErrorCode PCSetUp_PBJacobi_Kokkos(PC pc) 82 { 83 PC_PBJacobi *jac = (PC_PBJacobi *)pc->data; 84 PetscInt len; 85 86 PetscFunctionBegin; 87 PetscCall(PCSetUp_PBJacobi_Host(pc)); /* Compute the inverse on host now. Might worth doing it on device directly */ 88 len = jac->bs * jac->bs * jac->mbs; 89 if (!jac->spptr) { 90 PetscCallCXX(jac->spptr = new PC_PBJacobi_Kokkos(len, const_cast<PetscScalar *>(jac->diag))); 91 } else { 92 PC_PBJacobi_Kokkos *pckok = static_cast<PC_PBJacobi_Kokkos *>(jac->spptr); 93 PetscCall(pckok->Update(jac->diag)); 94 } 95 PetscCall(PetscLogCpuToGpu(sizeof(PetscScalar) * len)); 96 97 pc->ops->apply = PCApplyOrTranspose_PBJacobi_Kokkos<PETSC_FALSE>; 98 pc->ops->applytranspose = PCApplyOrTranspose_PBJacobi_Kokkos<PETSC_TRUE>; 99 pc->ops->destroy = PCDestroy_PBJacobi_Kokkos; 100 PetscFunctionReturn(PETSC_SUCCESS); 101 } 102