Actual source code: pbjacobi_kok.kokkos.cxx
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>
7: struct PC_PBJacobi_Kokkos {
8: PetscScalarKokkosDualView diag_dual;
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: }
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: };
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";
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;
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: }
72: static PetscErrorCode PCDestroy_PBJacobi_Kokkos(PC pc)
73: {
74: PC_PBJacobi *jac = (PC_PBJacobi *)pc->data;
76: PetscFunctionBegin;
77: PetscCallCXX(delete static_cast<PC_PBJacobi_Kokkos *>(jac->spptr));
78: PetscCall(PCDestroy_PBJacobi(pc));
79: PetscFunctionReturn(PETSC_SUCCESS);
80: }
82: PETSC_INTERN PetscErrorCode PCSetUp_PBJacobi_Kokkos(PC pc, Mat diagPB)
83: {
84: PC_PBJacobi *jac = (PC_PBJacobi *)pc->data;
85: PetscInt len;
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: }
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: }