cannam@167: /* cannam@167: * Copyright (c) 2003, 2007-14 Matteo Frigo cannam@167: * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology cannam@167: * cannam@167: * This program is free software; you can redistribute it and/or modify cannam@167: * it under the terms of the GNU General Public License as published by cannam@167: * the Free Software Foundation; either version 2 of the License, or cannam@167: * (at your option) any later version. cannam@167: * cannam@167: * This program is distributed in the hope that it will be useful, cannam@167: * but WITHOUT ANY WARRANTY; without even the implied warranty of cannam@167: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the cannam@167: * GNU General Public License for more details. cannam@167: * cannam@167: * You should have received a copy of the GNU General Public License cannam@167: * along with this program; if not, write to the Free Software cannam@167: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA cannam@167: * cannam@167: */ cannam@167: cannam@167: /* Distributed transposes using a sequence of carefully scheduled cannam@167: pairwise exchanges. This has the advantage that it can be done cannam@167: in-place, or out-of-place while preserving the input, using buffer cannam@167: space proportional to the local size divided by the number of cannam@167: processes (i.e. to the total array size divided by the number of cannam@167: processes squared). */ cannam@167: cannam@167: #include "mpi-transpose.h" cannam@167: #include cannam@167: cannam@167: typedef struct { cannam@167: solver super; cannam@167: int preserve_input; /* preserve input even if DESTROY_INPUT was passed */ cannam@167: } S; cannam@167: cannam@167: typedef struct { cannam@167: plan_mpi_transpose super; cannam@167: cannam@167: plan *cld1, *cld2, *cld2rest, *cld3; cannam@167: INT rest_Ioff, rest_Ooff; cannam@167: cannam@167: int n_pes, my_pe, *sched; cannam@167: INT *send_block_sizes, *send_block_offsets; cannam@167: INT *recv_block_sizes, *recv_block_offsets; cannam@167: MPI_Comm comm; cannam@167: int preserve_input; cannam@167: } P; cannam@167: cannam@167: static void transpose_chunks(int *sched, int n_pes, int my_pe, cannam@167: INT *sbs, INT *sbo, INT *rbs, INT *rbo, cannam@167: MPI_Comm comm, cannam@167: R *I, R *O) cannam@167: { cannam@167: if (sched) { cannam@167: int i; cannam@167: MPI_Status status; cannam@167: cannam@167: /* TODO: explore non-synchronous send/recv? */ cannam@167: cannam@167: if (I == O) { cannam@167: R *buf = (R*) MALLOC(sizeof(R) * sbs[0], BUFFERS); cannam@167: cannam@167: for (i = 0; i < n_pes; ++i) { cannam@167: int pe = sched[i]; cannam@167: if (my_pe == pe) { cannam@167: if (rbo[pe] != sbo[pe]) cannam@167: memmove(O + rbo[pe], O + sbo[pe], cannam@167: sbs[pe] * sizeof(R)); cannam@167: } cannam@167: else { cannam@167: memcpy(buf, O + sbo[pe], sbs[pe] * sizeof(R)); cannam@167: MPI_Sendrecv(buf, (int) (sbs[pe]), FFTW_MPI_TYPE, cannam@167: pe, (my_pe * n_pes + pe) & 0xffff, cannam@167: O + rbo[pe], (int) (rbs[pe]), cannam@167: FFTW_MPI_TYPE, cannam@167: pe, (pe * n_pes + my_pe) & 0xffff, cannam@167: comm, &status); cannam@167: } cannam@167: } cannam@167: cannam@167: X(ifree)(buf); cannam@167: } cannam@167: else { /* I != O */ cannam@167: for (i = 0; i < n_pes; ++i) { cannam@167: int pe = sched[i]; cannam@167: if (my_pe == pe) cannam@167: memcpy(O + rbo[pe], I + sbo[pe], sbs[pe] * sizeof(R)); cannam@167: else cannam@167: MPI_Sendrecv(I + sbo[pe], (int) (sbs[pe]), cannam@167: FFTW_MPI_TYPE, cannam@167: pe, (my_pe * n_pes + pe) & 0xffff, cannam@167: O + rbo[pe], (int) (rbs[pe]), cannam@167: FFTW_MPI_TYPE, cannam@167: pe, (pe * n_pes + my_pe) & 0xffff, cannam@167: comm, &status); cannam@167: } cannam@167: } cannam@167: } cannam@167: } cannam@167: cannam@167: static void apply(const plan *ego_, R *I, R *O) cannam@167: { cannam@167: const P *ego = (const P *) ego_; cannam@167: plan_rdft *cld1, *cld2, *cld2rest, *cld3; cannam@167: cannam@167: /* transpose locally to get contiguous chunks */ cannam@167: cld1 = (plan_rdft *) ego->cld1; cannam@167: if (cld1) { cannam@167: cld1->apply(ego->cld1, I, O); cannam@167: cannam@167: if (ego->preserve_input) I = O; cannam@167: cannam@167: /* transpose chunks globally */ cannam@167: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@167: ego->send_block_sizes, ego->send_block_offsets, cannam@167: ego->recv_block_sizes, ego->recv_block_offsets, cannam@167: ego->comm, O, I); cannam@167: } cannam@167: else if (ego->preserve_input) { cannam@167: /* transpose chunks globally */ cannam@167: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@167: ego->send_block_sizes, ego->send_block_offsets, cannam@167: ego->recv_block_sizes, ego->recv_block_offsets, cannam@167: ego->comm, I, O); cannam@167: cannam@167: I = O; cannam@167: } cannam@167: else { cannam@167: /* transpose chunks globally */ cannam@167: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@167: ego->send_block_sizes, ego->send_block_offsets, cannam@167: ego->recv_block_sizes, ego->recv_block_offsets, cannam@167: ego->comm, I, I); cannam@167: } cannam@167: cannam@167: /* transpose locally, again, to get ordinary row-major; cannam@167: this may take two transposes if the block sizes are unequal cannam@167: (3 subplans, two of which operate on disjoint data) */ cannam@167: cld2 = (plan_rdft *) ego->cld2; cannam@167: cld2->apply(ego->cld2, I, O); cannam@167: cld2rest = (plan_rdft *) ego->cld2rest; cannam@167: if (cld2rest) { cannam@167: cld2rest->apply(ego->cld2rest, cannam@167: I + ego->rest_Ioff, O + ego->rest_Ooff); cannam@167: cld3 = (plan_rdft *) ego->cld3; cannam@167: if (cld3) cannam@167: cld3->apply(ego->cld3, O, O); cannam@167: /* else TRANSPOSED_OUT is true and user wants O transposed */ cannam@167: } cannam@167: } cannam@167: cannam@167: static int applicable(const S *ego, const problem *p_, cannam@167: const planner *plnr) cannam@167: { cannam@167: const problem_mpi_transpose *p = (const problem_mpi_transpose *) p_; cannam@167: /* Note: this is *not* UGLY for out-of-place, destroy-input plans; cannam@167: the planner often prefers transpose-pairwise to transpose-alltoall, cannam@167: at least with LAM MPI on my machine. */ cannam@167: return (1 cannam@167: && (!ego->preserve_input || (!NO_DESTROY_INPUTP(plnr) cannam@167: && p->I != p->O)) cannam@167: && ONLY_TRANSPOSEDP(p->flags)); cannam@167: } cannam@167: cannam@167: static void awake(plan *ego_, enum wakefulness wakefulness) cannam@167: { cannam@167: P *ego = (P *) ego_; cannam@167: X(plan_awake)(ego->cld1, wakefulness); cannam@167: X(plan_awake)(ego->cld2, wakefulness); cannam@167: X(plan_awake)(ego->cld2rest, wakefulness); cannam@167: X(plan_awake)(ego->cld3, wakefulness); cannam@167: } cannam@167: cannam@167: static void destroy(plan *ego_) cannam@167: { cannam@167: P *ego = (P *) ego_; cannam@167: X(ifree0)(ego->sched); cannam@167: X(ifree0)(ego->send_block_sizes); cannam@167: MPI_Comm_free(&ego->comm); cannam@167: X(plan_destroy_internal)(ego->cld3); cannam@167: X(plan_destroy_internal)(ego->cld2rest); cannam@167: X(plan_destroy_internal)(ego->cld2); cannam@167: X(plan_destroy_internal)(ego->cld1); cannam@167: } cannam@167: cannam@167: static void print(const plan *ego_, printer *p) cannam@167: { cannam@167: const P *ego = (const P *) ego_; cannam@167: p->print(p, "(mpi-transpose-pairwise%s%(%p%)%(%p%)%(%p%)%(%p%))", cannam@167: ego->preserve_input==2 ?"/p":"", cannam@167: ego->cld1, ego->cld2, ego->cld2rest, ego->cld3); cannam@167: } cannam@167: cannam@167: /* Given a process which_pe and a number of processes npes, fills cannam@167: the array sched[npes] with a sequence of processes to communicate cannam@167: with for a deadlock-free, optimum-overlap all-to-all communication. cannam@167: (All processes must call this routine to get their own schedules.) cannam@167: The schedule can be re-ordered arbitrarily as long as all processes cannam@167: apply the same permutation to their schedules. cannam@167: cannam@167: The algorithm here is based upon the one described in: cannam@167: J. A. M. Schreuder, "Constructing timetables for sport cannam@167: competitions," Mathematical Programming Study 13, pp. 58-67 (1980). cannam@167: In a sport competition, you have N teams and want every team to cannam@167: play every other team in as short a time as possible (maximum overlap cannam@167: between games). This timetabling problem is therefore identical cannam@167: to that of an all-to-all communications problem. In our case, there cannam@167: is one wrinkle: as part of the schedule, the process must do cannam@167: some data transfer with itself (local data movement), analogous cannam@167: to a requirement that each team "play itself" in addition to other cannam@167: teams. With this wrinkle, it turns out that an optimal timetable cannam@167: (N parallel games) can be constructed for any N, not just for even cannam@167: N as in the original problem described by Schreuder. cannam@167: */ cannam@167: static void fill1_comm_sched(int *sched, int which_pe, int npes) cannam@167: { cannam@167: int pe, i, n, s = 0; cannam@167: A(which_pe >= 0 && which_pe < npes); cannam@167: if (npes % 2 == 0) { cannam@167: n = npes; cannam@167: sched[s++] = which_pe; cannam@167: } cannam@167: else cannam@167: n = npes + 1; cannam@167: for (pe = 0; pe < n - 1; ++pe) { cannam@167: if (npes % 2 == 0) { cannam@167: if (pe == which_pe) sched[s++] = npes - 1; cannam@167: else if (npes - 1 == which_pe) sched[s++] = pe; cannam@167: } cannam@167: else if (pe == which_pe) sched[s++] = pe; cannam@167: cannam@167: if (pe != which_pe && which_pe < n - 1) { cannam@167: i = (pe - which_pe + (n - 1)) % (n - 1); cannam@167: if (i < n/2) cannam@167: sched[s++] = (pe + i) % (n - 1); cannam@167: cannam@167: i = (which_pe - pe + (n - 1)) % (n - 1); cannam@167: if (i < n/2) cannam@167: sched[s++] = (pe - i + (n - 1)) % (n - 1); cannam@167: } cannam@167: } cannam@167: A(s == npes); cannam@167: } cannam@167: cannam@167: /* Sort the communication schedule sched for npes so that the schedule cannam@167: on process sortpe is ascending or descending (!ascending). This is cannam@167: necessary to allow in-place transposes when the problem does not cannam@167: divide equally among the processes. In this case there is one cannam@167: process where the incoming blocks are bigger/smaller than the cannam@167: outgoing blocks and thus have to be received in cannam@167: descending/ascending order, respectively, to avoid overwriting data cannam@167: before it is sent. */ cannam@167: static void sort1_comm_sched(int *sched, int npes, int sortpe, int ascending) cannam@167: { cannam@167: int *sortsched, i; cannam@167: sortsched = (int *) MALLOC(npes * sizeof(int) * 2, OTHER); cannam@167: fill1_comm_sched(sortsched, sortpe, npes); cannam@167: if (ascending) cannam@167: for (i = 0; i < npes; ++i) cannam@167: sortsched[npes + sortsched[i]] = sched[i]; cannam@167: else cannam@167: for (i = 0; i < npes; ++i) cannam@167: sortsched[2*npes - 1 - sortsched[i]] = sched[i]; cannam@167: for (i = 0; i < npes; ++i) cannam@167: sched[i] = sortsched[npes + i]; cannam@167: X(ifree)(sortsched); cannam@167: } cannam@167: cannam@167: /* make the plans to do the post-MPI transpositions (shared with cannam@167: transpose-alltoall) */ cannam@167: int XM(mkplans_posttranspose)(const problem_mpi_transpose *p, planner *plnr, cannam@167: R *I, R *O, int my_pe, cannam@167: plan **cld2, plan **cld2rest, plan **cld3, cannam@167: INT *rest_Ioff, INT *rest_Ooff) cannam@167: { cannam@167: INT vn = p->vn; cannam@167: INT b = p->block; cannam@167: INT bt = XM(block)(p->ny, p->tblock, my_pe); cannam@167: INT nxb = p->nx / b; /* number of equal-sized blocks */ cannam@167: INT nxr = p->nx - nxb * b; /* leftover rows after equal blocks */ cannam@167: cannam@167: *cld2 = *cld2rest = *cld3 = NULL; cannam@167: *rest_Ioff = *rest_Ooff = 0; cannam@167: cannam@167: if (!(p->flags & TRANSPOSED_OUT) && (nxr == 0 || I != O)) { cannam@167: INT nx = p->nx * vn; cannam@167: b *= vn; cannam@167: *cld2 = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)(X(mktensor_3d) cannam@167: (nxb, bt * b, b, cannam@167: bt, b, nx, cannam@167: b, 1, 1), cannam@167: I, O), cannam@167: 0, 0, NO_SLOW); cannam@167: if (!*cld2) goto nada; cannam@167: cannam@167: if (nxr > 0) { cannam@167: *rest_Ioff = nxb * bt * b; cannam@167: *rest_Ooff = nxb * b; cannam@167: b = nxr * vn; cannam@167: *cld2rest = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)(X(mktensor_2d) cannam@167: (bt, b, nx, cannam@167: b, 1, 1), cannam@167: I + *rest_Ioff, cannam@167: O + *rest_Ooff), cannam@167: 0, 0, NO_SLOW); cannam@167: if (!*cld2rest) goto nada; cannam@167: } cannam@167: } cannam@167: else { cannam@167: *cld2 = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)( cannam@167: X(mktensor_4d) cannam@167: (nxb, bt * b * vn, bt * b * vn, cannam@167: bt, b * vn, vn, cannam@167: b, vn, bt * vn, cannam@167: vn, 1, 1), cannam@167: I, O), cannam@167: 0, 0, NO_SLOW); cannam@167: if (!*cld2) goto nada; cannam@167: cannam@167: *rest_Ioff = *rest_Ooff = nxb * bt * b * vn; cannam@167: *cld2rest = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)( cannam@167: X(mktensor_3d) cannam@167: (bt, nxr * vn, vn, cannam@167: nxr, vn, bt * vn, cannam@167: vn, 1, 1), cannam@167: I + *rest_Ioff, O + *rest_Ooff), cannam@167: 0, 0, NO_SLOW); cannam@167: if (!*cld2rest) goto nada; cannam@167: cannam@167: if (!(p->flags & TRANSPOSED_OUT)) { cannam@167: *cld3 = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)( cannam@167: X(mktensor_3d) cannam@167: (p->nx, bt * vn, vn, cannam@167: bt, vn, p->nx * vn, cannam@167: vn, 1, 1), cannam@167: O, O), cannam@167: 0, 0, NO_SLOW); cannam@167: if (!*cld3) goto nada; cannam@167: } cannam@167: } cannam@167: cannam@167: return 1; cannam@167: cannam@167: nada: cannam@167: X(plan_destroy_internal)(*cld3); cannam@167: X(plan_destroy_internal)(*cld2rest); cannam@167: X(plan_destroy_internal)(*cld2); cannam@167: *cld2 = *cld2rest = *cld3 = NULL; cannam@167: return 0; cannam@167: } cannam@167: cannam@167: static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr) cannam@167: { cannam@167: const S *ego = (const S *) ego_; cannam@167: const problem_mpi_transpose *p; cannam@167: P *pln; cannam@167: plan *cld1 = 0, *cld2 = 0, *cld2rest = 0, *cld3 = 0; cannam@167: INT b, bt, vn, rest_Ioff, rest_Ooff; cannam@167: INT *sbs, *sbo, *rbs, *rbo; cannam@167: int pe, my_pe, n_pes, sort_pe = -1, ascending = 1; cannam@167: R *I, *O; cannam@167: static const plan_adt padt = { cannam@167: XM(transpose_solve), awake, print, destroy cannam@167: }; cannam@167: cannam@167: UNUSED(ego); cannam@167: cannam@167: if (!applicable(ego, p_, plnr)) cannam@167: return (plan *) 0; cannam@167: cannam@167: p = (const problem_mpi_transpose *) p_; cannam@167: vn = p->vn; cannam@167: I = p->I; O = p->O; cannam@167: cannam@167: MPI_Comm_rank(p->comm, &my_pe); cannam@167: MPI_Comm_size(p->comm, &n_pes); cannam@167: cannam@167: b = XM(block)(p->nx, p->block, my_pe); cannam@167: cannam@167: if (!(p->flags & TRANSPOSED_IN)) { /* b x ny x vn -> ny x b x vn */ cannam@167: cld1 = X(mkplan_f_d)(plnr, cannam@167: X(mkproblem_rdft_0_d)(X(mktensor_3d) cannam@167: (b, p->ny * vn, vn, cannam@167: p->ny, vn, b * vn, cannam@167: vn, 1, 1), cannam@167: I, O), cannam@167: 0, 0, NO_SLOW); cannam@167: if (XM(any_true)(!cld1, p->comm)) goto nada; cannam@167: } cannam@167: if (ego->preserve_input || NO_DESTROY_INPUTP(plnr)) I = O; cannam@167: cannam@167: if (XM(any_true)(!XM(mkplans_posttranspose)(p, plnr, I, O, my_pe, cannam@167: &cld2, &cld2rest, &cld3, cannam@167: &rest_Ioff, &rest_Ooff), cannam@167: p->comm)) goto nada; cannam@167: cannam@167: pln = MKPLAN_MPI_TRANSPOSE(P, &padt, apply); cannam@167: cannam@167: pln->cld1 = cld1; cannam@167: pln->cld2 = cld2; cannam@167: pln->cld2rest = cld2rest; cannam@167: pln->rest_Ioff = rest_Ioff; cannam@167: pln->rest_Ooff = rest_Ooff; cannam@167: pln->cld3 = cld3; cannam@167: pln->preserve_input = ego->preserve_input ? 2 : NO_DESTROY_INPUTP(plnr); cannam@167: cannam@167: MPI_Comm_dup(p->comm, &pln->comm); cannam@167: cannam@167: n_pes = (int) X(imax)(XM(num_blocks)(p->nx, p->block), cannam@167: XM(num_blocks)(p->ny, p->tblock)); cannam@167: cannam@167: /* Compute sizes/offsets of blocks to exchange between processors */ cannam@167: sbs = (INT *) MALLOC(4 * n_pes * sizeof(INT), PLANS); cannam@167: sbo = sbs + n_pes; cannam@167: rbs = sbo + n_pes; cannam@167: rbo = rbs + n_pes; cannam@167: b = XM(block)(p->nx, p->block, my_pe); cannam@167: bt = XM(block)(p->ny, p->tblock, my_pe); cannam@167: for (pe = 0; pe < n_pes; ++pe) { cannam@167: INT db, dbt; /* destination block sizes */ cannam@167: db = XM(block)(p->nx, p->block, pe); cannam@167: dbt = XM(block)(p->ny, p->tblock, pe); cannam@167: cannam@167: sbs[pe] = b * dbt * vn; cannam@167: sbo[pe] = pe * (b * p->tblock) * vn; cannam@167: rbs[pe] = db * bt * vn; cannam@167: rbo[pe] = pe * (p->block * bt) * vn; cannam@167: cannam@167: if (db * dbt > 0 && db * p->tblock != p->block * dbt) { cannam@167: A(sort_pe == -1); /* only one process should need sorting */ cannam@167: sort_pe = pe; cannam@167: ascending = db * p->tblock > p->block * dbt; cannam@167: } cannam@167: } cannam@167: pln->n_pes = n_pes; cannam@167: pln->my_pe = my_pe; cannam@167: pln->send_block_sizes = sbs; cannam@167: pln->send_block_offsets = sbo; cannam@167: pln->recv_block_sizes = rbs; cannam@167: pln->recv_block_offsets = rbo; cannam@167: cannam@167: if (my_pe >= n_pes) { cannam@167: pln->sched = 0; /* this process is not doing anything */ cannam@167: } cannam@167: else { cannam@167: pln->sched = (int *) MALLOC(n_pes * sizeof(int), PLANS); cannam@167: fill1_comm_sched(pln->sched, my_pe, n_pes); cannam@167: if (sort_pe >= 0) cannam@167: sort1_comm_sched(pln->sched, n_pes, sort_pe, ascending); cannam@167: } cannam@167: cannam@167: X(ops_zero)(&pln->super.super.ops); cannam@167: if (cld1) X(ops_add2)(&cld1->ops, &pln->super.super.ops); cannam@167: if (cld2) X(ops_add2)(&cld2->ops, &pln->super.super.ops); cannam@167: if (cld2rest) X(ops_add2)(&cld2rest->ops, &pln->super.super.ops); cannam@167: if (cld3) X(ops_add2)(&cld3->ops, &pln->super.super.ops); cannam@167: /* FIXME: should MPI operations be counted in "other" somehow? */ cannam@167: cannam@167: return &(pln->super.super); cannam@167: cannam@167: nada: cannam@167: X(plan_destroy_internal)(cld3); cannam@167: X(plan_destroy_internal)(cld2rest); cannam@167: X(plan_destroy_internal)(cld2); cannam@167: X(plan_destroy_internal)(cld1); cannam@167: return (plan *) 0; cannam@167: } cannam@167: cannam@167: static solver *mksolver(int preserve_input) cannam@167: { cannam@167: static const solver_adt sadt = { PROBLEM_MPI_TRANSPOSE, mkplan, 0 }; cannam@167: S *slv = MKSOLVER(S, &sadt); cannam@167: slv->preserve_input = preserve_input; cannam@167: return &(slv->super); cannam@167: } cannam@167: cannam@167: void XM(transpose_pairwise_register)(planner *p) cannam@167: { cannam@167: int preserve_input; cannam@167: for (preserve_input = 0; preserve_input <= 1; ++preserve_input) cannam@167: REGISTER_SOLVER(p, mksolver(preserve_input)); cannam@167: }