cannam@95: /* cannam@95: * Copyright (c) 2003, 2007-11 Matteo Frigo cannam@95: * Copyright (c) 2003, 2007-11 Massachusetts Institute of Technology cannam@95: * cannam@95: * This program is free software; you can redistribute it and/or modify cannam@95: * it under the terms of the GNU General Public License as published by cannam@95: * the Free Software Foundation; either version 2 of the License, or cannam@95: * (at your option) any later version. cannam@95: * cannam@95: * This program is distributed in the hope that it will be useful, cannam@95: * but WITHOUT ANY WARRANTY; without even the implied warranty of cannam@95: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the cannam@95: * GNU General Public License for more details. cannam@95: * cannam@95: * You should have received a copy of the GNU General Public License cannam@95: * along with this program; if not, write to the Free Software cannam@95: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA cannam@95: * cannam@95: */ cannam@95: cannam@95: /* Distributed transposes using a sequence of carefully scheduled cannam@95: pairwise exchanges. This has the advantage that it can be done cannam@95: in-place, or out-of-place while preserving the input, using buffer cannam@95: space proportional to the local size divided by the number of cannam@95: processes (i.e. to the total array size divided by the number of cannam@95: processes squared). */ cannam@95: cannam@95: #include "mpi-transpose.h" cannam@95: #include cannam@95: cannam@95: typedef struct { cannam@95: solver super; cannam@95: int preserve_input; /* preserve input even if DESTROY_INPUT was passed */ cannam@95: } S; cannam@95: cannam@95: typedef struct { cannam@95: plan_mpi_transpose super; cannam@95: cannam@95: plan *cld1, *cld2, *cld2rest, *cld3; cannam@95: INT rest_Ioff, rest_Ooff; cannam@95: cannam@95: int n_pes, my_pe, *sched; cannam@95: INT *send_block_sizes, *send_block_offsets; cannam@95: INT *recv_block_sizes, *recv_block_offsets; cannam@95: MPI_Comm comm; cannam@95: int preserve_input; cannam@95: } P; cannam@95: cannam@95: static void transpose_chunks(int *sched, int n_pes, int my_pe, cannam@95: INT *sbs, INT *sbo, INT *rbs, INT *rbo, cannam@95: MPI_Comm comm, cannam@95: R *I, R *O) cannam@95: { cannam@95: if (sched) { cannam@95: int i; cannam@95: MPI_Status status; cannam@95: cannam@95: /* TODO: explore non-synchronous send/recv? */ cannam@95: cannam@95: if (I == O) { cannam@95: R *buf = (R*) MALLOC(sizeof(R) * sbs[0], BUFFERS); cannam@95: cannam@95: for (i = 0; i < n_pes; ++i) { cannam@95: int pe = sched[i]; cannam@95: if (my_pe == pe) { cannam@95: if (rbo[pe] != sbo[pe]) cannam@95: memmove(O + rbo[pe], O + sbo[pe], cannam@95: sbs[pe] * sizeof(R)); cannam@95: } cannam@95: else { cannam@95: memcpy(buf, O + sbo[pe], sbs[pe] * sizeof(R)); cannam@95: MPI_Sendrecv(buf, (int) (sbs[pe]), FFTW_MPI_TYPE, cannam@95: pe, (my_pe * n_pes + pe) & 0xffff, cannam@95: O + rbo[pe], (int) (rbs[pe]), cannam@95: FFTW_MPI_TYPE, cannam@95: pe, (pe * n_pes + my_pe) & 0xffff, cannam@95: comm, &status); cannam@95: } cannam@95: } cannam@95: cannam@95: X(ifree)(buf); cannam@95: } cannam@95: else { /* I != O */ cannam@95: for (i = 0; i < n_pes; ++i) { cannam@95: int pe = sched[i]; cannam@95: if (my_pe == pe) cannam@95: memcpy(O + rbo[pe], I + sbo[pe], sbs[pe] * sizeof(R)); cannam@95: else cannam@95: MPI_Sendrecv(I + sbo[pe], (int) (sbs[pe]), cannam@95: FFTW_MPI_TYPE, cannam@95: pe, (my_pe * n_pes + pe) & 0xffff, cannam@95: O + rbo[pe], (int) (rbs[pe]), cannam@95: FFTW_MPI_TYPE, cannam@95: pe, (pe * n_pes + my_pe) & 0xffff, cannam@95: comm, &status); cannam@95: } cannam@95: } cannam@95: } cannam@95: } cannam@95: cannam@95: static void apply(const plan *ego_, R *I, R *O) cannam@95: { cannam@95: const P *ego = (const P *) ego_; cannam@95: plan_rdft *cld1, *cld2, *cld2rest, *cld3; cannam@95: cannam@95: /* transpose locally to get contiguous chunks */ cannam@95: cld1 = (plan_rdft *) ego->cld1; cannam@95: if (cld1) { cannam@95: cld1->apply(ego->cld1, I, O); cannam@95: cannam@95: if (ego->preserve_input) I = O; cannam@95: cannam@95: /* transpose chunks globally */ cannam@95: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@95: ego->send_block_sizes, ego->send_block_offsets, cannam@95: ego->recv_block_sizes, ego->recv_block_offsets, cannam@95: ego->comm, O, I); cannam@95: } cannam@95: else if (ego->preserve_input) { cannam@95: /* transpose chunks globally */ cannam@95: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@95: ego->send_block_sizes, ego->send_block_offsets, cannam@95: ego->recv_block_sizes, ego->recv_block_offsets, cannam@95: ego->comm, I, O); cannam@95: cannam@95: I = O; cannam@95: } cannam@95: else { cannam@95: /* transpose chunks globally */ cannam@95: transpose_chunks(ego->sched, ego->n_pes, ego->my_pe, cannam@95: ego->send_block_sizes, ego->send_block_offsets, cannam@95: ego->recv_block_sizes, ego->recv_block_offsets, cannam@95: ego->comm, I, I); cannam@95: } cannam@95: cannam@95: /* transpose locally, again, to get ordinary row-major; cannam@95: this may take two transposes if the block sizes are unequal cannam@95: (3 subplans, two of which operate on disjoint data) */ cannam@95: cld2 = (plan_rdft *) ego->cld2; cannam@95: cld2->apply(ego->cld2, I, O); cannam@95: cld2rest = (plan_rdft *) ego->cld2rest; cannam@95: if (cld2rest) { cannam@95: cld2rest->apply(ego->cld2rest, cannam@95: I + ego->rest_Ioff, O + ego->rest_Ooff); cannam@95: cld3 = (plan_rdft *) ego->cld3; cannam@95: if (cld3) cannam@95: cld3->apply(ego->cld3, O, O); cannam@95: /* else TRANSPOSED_OUT is true and user wants O transposed */ cannam@95: } cannam@95: } cannam@95: cannam@95: static int applicable(const S *ego, const problem *p_, cannam@95: const planner *plnr) cannam@95: { cannam@95: const problem_mpi_transpose *p = (const problem_mpi_transpose *) p_; cannam@95: /* Note: this is *not* UGLY for out-of-place, destroy-input plans; cannam@95: the planner often prefers transpose-pairwise to transpose-alltoall, cannam@95: at least with LAM MPI on my machine. */ cannam@95: return (1 cannam@95: && (!ego->preserve_input || (!NO_DESTROY_INPUTP(plnr) cannam@95: && p->I != p->O)) cannam@95: && ONLY_TRANSPOSEDP(p->flags)); cannam@95: } cannam@95: cannam@95: static void awake(plan *ego_, enum wakefulness wakefulness) cannam@95: { cannam@95: P *ego = (P *) ego_; cannam@95: X(plan_awake)(ego->cld1, wakefulness); cannam@95: X(plan_awake)(ego->cld2, wakefulness); cannam@95: X(plan_awake)(ego->cld2rest, wakefulness); cannam@95: X(plan_awake)(ego->cld3, wakefulness); cannam@95: } cannam@95: cannam@95: static void destroy(plan *ego_) cannam@95: { cannam@95: P *ego = (P *) ego_; cannam@95: X(ifree0)(ego->sched); cannam@95: X(ifree0)(ego->send_block_sizes); cannam@95: MPI_Comm_free(&ego->comm); cannam@95: X(plan_destroy_internal)(ego->cld3); cannam@95: X(plan_destroy_internal)(ego->cld2rest); cannam@95: X(plan_destroy_internal)(ego->cld2); cannam@95: X(plan_destroy_internal)(ego->cld1); cannam@95: } cannam@95: cannam@95: static void print(const plan *ego_, printer *p) cannam@95: { cannam@95: const P *ego = (const P *) ego_; cannam@95: p->print(p, "(mpi-transpose-pairwise%s%(%p%)%(%p%)%(%p%)%(%p%))", cannam@95: ego->preserve_input==2 ?"/p":"", cannam@95: ego->cld1, ego->cld2, ego->cld2rest, ego->cld3); cannam@95: } cannam@95: cannam@95: /* Given a process which_pe and a number of processes npes, fills cannam@95: the array sched[npes] with a sequence of processes to communicate cannam@95: with for a deadlock-free, optimum-overlap all-to-all communication. cannam@95: (All processes must call this routine to get their own schedules.) cannam@95: The schedule can be re-ordered arbitrarily as long as all processes cannam@95: apply the same permutation to their schedules. cannam@95: cannam@95: The algorithm here is based upon the one described in: cannam@95: J. A. M. Schreuder, "Constructing timetables for sport cannam@95: competitions," Mathematical Programming Study 13, pp. 58-67 (1980). cannam@95: In a sport competition, you have N teams and want every team to cannam@95: play every other team in as short a time as possible (maximum overlap cannam@95: between games). This timetabling problem is therefore identical cannam@95: to that of an all-to-all communications problem. In our case, there cannam@95: is one wrinkle: as part of the schedule, the process must do cannam@95: some data transfer with itself (local data movement), analogous cannam@95: to a requirement that each team "play itself" in addition to other cannam@95: teams. With this wrinkle, it turns out that an optimal timetable cannam@95: (N parallel games) can be constructed for any N, not just for even cannam@95: N as in the original problem described by Schreuder. cannam@95: */ cannam@95: static void fill1_comm_sched(int *sched, int which_pe, int npes) cannam@95: { cannam@95: int pe, i, n, s = 0; cannam@95: A(which_pe >= 0 && which_pe < npes); cannam@95: if (npes % 2 == 0) { cannam@95: n = npes; cannam@95: sched[s++] = which_pe; cannam@95: } cannam@95: else cannam@95: n = npes + 1; cannam@95: for (pe = 0; pe < n - 1; ++pe) { cannam@95: if (npes % 2 == 0) { cannam@95: if (pe == which_pe) sched[s++] = npes - 1; cannam@95: else if (npes - 1 == which_pe) sched[s++] = pe; cannam@95: } cannam@95: else if (pe == which_pe) sched[s++] = pe; cannam@95: cannam@95: if (pe != which_pe && which_pe < n - 1) { cannam@95: i = (pe - which_pe + (n - 1)) % (n - 1); cannam@95: if (i < n/2) cannam@95: sched[s++] = (pe + i) % (n - 1); cannam@95: cannam@95: i = (which_pe - pe + (n - 1)) % (n - 1); cannam@95: if (i < n/2) cannam@95: sched[s++] = (pe - i + (n - 1)) % (n - 1); cannam@95: } cannam@95: } cannam@95: A(s == npes); cannam@95: } cannam@95: cannam@95: /* Sort the communication schedule sched for npes so that the schedule cannam@95: on process sortpe is ascending or descending (!ascending). This is cannam@95: necessary to allow in-place transposes when the problem does not cannam@95: divide equally among the processes. In this case there is one cannam@95: process where the incoming blocks are bigger/smaller than the cannam@95: outgoing blocks and thus have to be received in cannam@95: descending/ascending order, respectively, to avoid overwriting data cannam@95: before it is sent. */ cannam@95: static void sort1_comm_sched(int *sched, int npes, int sortpe, int ascending) cannam@95: { cannam@95: int *sortsched, i; cannam@95: sortsched = (int *) MALLOC(npes * sizeof(int) * 2, OTHER); cannam@95: fill1_comm_sched(sortsched, sortpe, npes); cannam@95: if (ascending) cannam@95: for (i = 0; i < npes; ++i) cannam@95: sortsched[npes + sortsched[i]] = sched[i]; cannam@95: else cannam@95: for (i = 0; i < npes; ++i) cannam@95: sortsched[2*npes - 1 - sortsched[i]] = sched[i]; cannam@95: for (i = 0; i < npes; ++i) cannam@95: sched[i] = sortsched[npes + i]; cannam@95: X(ifree)(sortsched); cannam@95: } cannam@95: cannam@95: /* make the plans to do the post-MPI transpositions (shared with cannam@95: transpose-alltoall) */ cannam@95: int XM(mkplans_posttranspose)(const problem_mpi_transpose *p, planner *plnr, cannam@95: R *I, R *O, int my_pe, cannam@95: plan **cld2, plan **cld2rest, plan **cld3, cannam@95: INT *rest_Ioff, INT *rest_Ooff) cannam@95: { cannam@95: INT vn = p->vn; cannam@95: INT b = p->block; cannam@95: INT bt = XM(block)(p->ny, p->tblock, my_pe); cannam@95: INT nxb = p->nx / b; /* number of equal-sized blocks */ cannam@95: INT nxr = p->nx - nxb * b; /* leftover rows after equal blocks */ cannam@95: cannam@95: *cld2 = *cld2rest = *cld3 = NULL; cannam@95: *rest_Ioff = *rest_Ooff = 0; cannam@95: cannam@95: if (!(p->flags & TRANSPOSED_OUT) && (nxr == 0 || I != O)) { cannam@95: INT nx = p->nx * vn; cannam@95: b *= vn; cannam@95: *cld2 = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)(X(mktensor_3d) cannam@95: (nxb, bt * b, b, cannam@95: bt, b, nx, cannam@95: b, 1, 1), cannam@95: I, O), cannam@95: 0, 0, NO_SLOW); cannam@95: if (!*cld2) goto nada; cannam@95: cannam@95: if (nxr > 0) { cannam@95: *rest_Ioff = nxb * bt * b; cannam@95: *rest_Ooff = nxb * b; cannam@95: b = nxr * vn; cannam@95: *cld2rest = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)(X(mktensor_2d) cannam@95: (bt, b, nx, cannam@95: b, 1, 1), cannam@95: I + *rest_Ioff, cannam@95: O + *rest_Ooff), cannam@95: 0, 0, NO_SLOW); cannam@95: if (!*cld2rest) goto nada; cannam@95: } cannam@95: } cannam@95: else { cannam@95: *cld2 = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)( cannam@95: X(mktensor_4d) cannam@95: (nxb, bt * b * vn, bt * b * vn, cannam@95: bt, b * vn, vn, cannam@95: b, vn, bt * vn, cannam@95: vn, 1, 1), cannam@95: I, O), cannam@95: 0, 0, NO_SLOW); cannam@95: if (!*cld2) goto nada; cannam@95: cannam@95: *rest_Ioff = *rest_Ooff = nxb * bt * b * vn; cannam@95: *cld2rest = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)( cannam@95: X(mktensor_3d) cannam@95: (bt, nxr * vn, vn, cannam@95: nxr, vn, bt * vn, cannam@95: vn, 1, 1), cannam@95: I + *rest_Ioff, O + *rest_Ooff), cannam@95: 0, 0, NO_SLOW); cannam@95: if (!*cld2rest) goto nada; cannam@95: cannam@95: if (!(p->flags & TRANSPOSED_OUT)) { cannam@95: *cld3 = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)( cannam@95: X(mktensor_3d) cannam@95: (p->nx, bt * vn, vn, cannam@95: bt, vn, p->nx * vn, cannam@95: vn, 1, 1), cannam@95: O, O), cannam@95: 0, 0, NO_SLOW); cannam@95: if (!*cld3) goto nada; cannam@95: } cannam@95: } cannam@95: cannam@95: return 1; cannam@95: cannam@95: nada: cannam@95: X(plan_destroy_internal)(*cld3); cannam@95: X(plan_destroy_internal)(*cld2rest); cannam@95: X(plan_destroy_internal)(*cld2); cannam@95: return 0; cannam@95: } cannam@95: cannam@95: static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr) cannam@95: { cannam@95: const S *ego = (const S *) ego_; cannam@95: const problem_mpi_transpose *p; cannam@95: P *pln; cannam@95: plan *cld1 = 0, *cld2 = 0, *cld2rest = 0, *cld3 = 0; cannam@95: INT b, bt, vn, rest_Ioff, rest_Ooff; cannam@95: INT *sbs, *sbo, *rbs, *rbo; cannam@95: int pe, my_pe, n_pes, sort_pe = -1, ascending = 1; cannam@95: R *I, *O; cannam@95: static const plan_adt padt = { cannam@95: XM(transpose_solve), awake, print, destroy cannam@95: }; cannam@95: cannam@95: UNUSED(ego); cannam@95: cannam@95: if (!applicable(ego, p_, plnr)) cannam@95: return (plan *) 0; cannam@95: cannam@95: p = (const problem_mpi_transpose *) p_; cannam@95: vn = p->vn; cannam@95: I = p->I; O = p->O; cannam@95: cannam@95: MPI_Comm_rank(p->comm, &my_pe); cannam@95: MPI_Comm_size(p->comm, &n_pes); cannam@95: cannam@95: b = XM(block)(p->nx, p->block, my_pe); cannam@95: cannam@95: if (!(p->flags & TRANSPOSED_IN)) { /* b x ny x vn -> ny x b x vn */ cannam@95: cld1 = X(mkplan_f_d)(plnr, cannam@95: X(mkproblem_rdft_0_d)(X(mktensor_3d) cannam@95: (b, p->ny * vn, vn, cannam@95: p->ny, vn, b * vn, cannam@95: vn, 1, 1), cannam@95: I, O), cannam@95: 0, 0, NO_SLOW); cannam@95: if (XM(any_true)(!cld1, p->comm)) goto nada; cannam@95: } cannam@95: if (ego->preserve_input || NO_DESTROY_INPUTP(plnr)) I = O; cannam@95: cannam@95: if (XM(any_true)(!XM(mkplans_posttranspose)(p, plnr, I, O, my_pe, cannam@95: &cld2, &cld2rest, &cld3, cannam@95: &rest_Ioff, &rest_Ooff), cannam@95: p->comm)) goto nada; cannam@95: cannam@95: pln = MKPLAN_MPI_TRANSPOSE(P, &padt, apply); cannam@95: cannam@95: pln->cld1 = cld1; cannam@95: pln->cld2 = cld2; cannam@95: pln->cld2rest = cld2rest; cannam@95: pln->rest_Ioff = rest_Ioff; cannam@95: pln->rest_Ooff = rest_Ooff; cannam@95: pln->cld3 = cld3; cannam@95: pln->preserve_input = ego->preserve_input ? 2 : NO_DESTROY_INPUTP(plnr); cannam@95: cannam@95: MPI_Comm_dup(p->comm, &pln->comm); cannam@95: cannam@95: n_pes = (int) X(imax)(XM(num_blocks)(p->nx, p->block), cannam@95: XM(num_blocks)(p->ny, p->tblock)); cannam@95: cannam@95: /* Compute sizes/offsets of blocks to exchange between processors */ cannam@95: sbs = (INT *) MALLOC(4 * n_pes * sizeof(INT), PLANS); cannam@95: sbo = sbs + n_pes; cannam@95: rbs = sbo + n_pes; cannam@95: rbo = rbs + n_pes; cannam@95: b = XM(block)(p->nx, p->block, my_pe); cannam@95: bt = XM(block)(p->ny, p->tblock, my_pe); cannam@95: for (pe = 0; pe < n_pes; ++pe) { cannam@95: INT db, dbt; /* destination block sizes */ cannam@95: db = XM(block)(p->nx, p->block, pe); cannam@95: dbt = XM(block)(p->ny, p->tblock, pe); cannam@95: cannam@95: sbs[pe] = b * dbt * vn; cannam@95: sbo[pe] = pe * (b * p->tblock) * vn; cannam@95: rbs[pe] = db * bt * vn; cannam@95: rbo[pe] = pe * (p->block * bt) * vn; cannam@95: cannam@95: if (db * dbt > 0 && db * p->tblock != p->block * dbt) { cannam@95: A(sort_pe == -1); /* only one process should need sorting */ cannam@95: sort_pe = pe; cannam@95: ascending = db * p->tblock > p->block * dbt; cannam@95: } cannam@95: } cannam@95: pln->n_pes = n_pes; cannam@95: pln->my_pe = my_pe; cannam@95: pln->send_block_sizes = sbs; cannam@95: pln->send_block_offsets = sbo; cannam@95: pln->recv_block_sizes = rbs; cannam@95: pln->recv_block_offsets = rbo; cannam@95: cannam@95: if (my_pe >= n_pes) { cannam@95: pln->sched = 0; /* this process is not doing anything */ cannam@95: } cannam@95: else { cannam@95: pln->sched = (int *) MALLOC(n_pes * sizeof(int), PLANS); cannam@95: fill1_comm_sched(pln->sched, my_pe, n_pes); cannam@95: if (sort_pe >= 0) cannam@95: sort1_comm_sched(pln->sched, n_pes, sort_pe, ascending); cannam@95: } cannam@95: cannam@95: X(ops_zero)(&pln->super.super.ops); cannam@95: if (cld1) X(ops_add2)(&cld1->ops, &pln->super.super.ops); cannam@95: if (cld2) X(ops_add2)(&cld2->ops, &pln->super.super.ops); cannam@95: if (cld2rest) X(ops_add2)(&cld2rest->ops, &pln->super.super.ops); cannam@95: if (cld3) X(ops_add2)(&cld3->ops, &pln->super.super.ops); cannam@95: /* FIXME: should MPI operations be counted in "other" somehow? */ cannam@95: cannam@95: return &(pln->super.super); cannam@95: cannam@95: nada: cannam@95: X(plan_destroy_internal)(cld3); cannam@95: X(plan_destroy_internal)(cld2rest); cannam@95: X(plan_destroy_internal)(cld2); cannam@95: X(plan_destroy_internal)(cld1); cannam@95: return (plan *) 0; cannam@95: } cannam@95: cannam@95: static solver *mksolver(int preserve_input) cannam@95: { cannam@95: static const solver_adt sadt = { PROBLEM_MPI_TRANSPOSE, mkplan, 0 }; cannam@95: S *slv = MKSOLVER(S, &sadt); cannam@95: slv->preserve_input = preserve_input; cannam@95: return &(slv->super); cannam@95: } cannam@95: cannam@95: void XM(transpose_pairwise_register)(planner *p) cannam@95: { cannam@95: int preserve_input; cannam@95: for (preserve_input = 0; preserve_input <= 1; ++preserve_input) cannam@95: REGISTER_SOLVER(p, mksolver(preserve_input)); cannam@95: }