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