/* * Copyright (c) 2006 The Trustees of Indiana University and Indiana * University Research and Technology * Corporation. All rights reserved. * Copyright (c) 2006 The Technical University of Chemnitz. All * rights reserved. * * Author(s): Torsten Hoefler * */ #include "nbc_internal.h" #include static inline int allred_sched_diss(int rank, int p, int count, MPI_Datatype datatype, void *sendbuf, void *recvbuf, MPI_Op op, NBC_Schedule *schedule, NBC_Handle *handle); static inline int allred_sched_ring(int rank, int p, int count, MPI_Datatype datatype, void *sendbuf, void *recvbuf, MPI_Op op, int size, int ext, NBC_Schedule *schedule, NBC_Handle *handle); #ifdef NBC_CACHE_SCHEDULE /* tree comparison function for schedule cache */ int NBC_Allreduce_args_compare(NBC_Allreduce_args *a, NBC_Allreduce_args *b, void *param) { if( (a->sendbuf == b->sendbuf) && (a->recvbuf == b->recvbuf) && (a->count == b->count) && (a->datatype == b->datatype) && (a->op == b->op) ) { return 0; } if( a->sendbuf < b->sendbuf ) { return -1; } return +1; } #endif int ompi_coll_libnbc_iallreduce(void* sendbuf, void* recvbuf, int count, MPI_Datatype datatype, MPI_Op op, struct ompi_communicator_t *comm, ompi_request_t ** request, struct mca_coll_base_module_2_0_0_t *module) { int rank, p, res, size; MPI_Aint ext; NBC_Schedule *schedule; #ifdef NBC_CACHE_SCHEDULE NBC_Allreduce_args *args, *found, search; #endif enum { NBC_ARED_BINOMIAL, NBC_ARED_RING } alg; char inplace; NBC_Handle *handle; ompi_coll_libnbc_request_t **coll_req = (ompi_coll_libnbc_request_t**) request; ompi_coll_libnbc_module_t *libnbc_module = (ompi_coll_libnbc_module_t*) module; NBC_IN_PLACE(sendbuf, recvbuf, inplace); res = NBC_Init_handle(comm, coll_req, libnbc_module); if(res != NBC_OK) { printf("Error in NBC_Init_handle(%i)\n", res); return res; } handle = (*coll_req); res = MPI_Comm_rank(comm, &rank); if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_rank() (%i)\n", res); return res; } res = MPI_Comm_size(comm, &p); if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Comm_size() (%i)\n", res); return res; } res = MPI_Type_extent(datatype, &ext); if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Type_extent() (%i)\n", res); return res; } res = MPI_Type_size(datatype, &size); if (MPI_SUCCESS != res) { printf("MPI Error in MPI_Type_size() (%i)\n", res); return res; } handle->tmpbuf = malloc(ext*count); if(handle->tmpbuf == NULL) { printf("Error in malloc() (%i)\n", res); return NBC_OOR; } if((p == 1) && !inplace) { /* for a single node - copy data to receivebuf */ res = NBC_Copy(sendbuf, count, datatype, recvbuf, count, datatype, comm); if (NBC_OK != res) { printf("Error in NBC_Copy() (%i)\n", res); return res; } } /* algorithm selection */ if(p < 4 || size*count < 65536 || inplace) { alg = NBC_ARED_BINOMIAL; } else { alg = NBC_ARED_RING; } #ifdef NBC_CACHE_SCHEDULE /* search schedule in communicator specific tree */ search.sendbuf=sendbuf; search.recvbuf=recvbuf; search.count=count; search.datatype=datatype; search.op=op; found = (NBC_Allreduce_args*)hb_tree_search((hb_tree*)handle->comminfo->NBC_Dict[NBC_ALLREDUCE], &search); if(found == NULL) { #endif schedule = (NBC_Schedule*)malloc(sizeof(NBC_Schedule)); if (NULL == schedule) { printf("Error in malloc()\n"); return res; } res = NBC_Sched_create(schedule); if(res != NBC_OK) { printf("Error in NBC_Sched_create (%i)\n", res); return res; } switch(alg) { case NBC_ARED_BINOMIAL: res = allred_sched_diss(rank, p, count, datatype, sendbuf, recvbuf, op, schedule, handle); break; case NBC_ARED_RING: res = allred_sched_ring(rank, p, count, datatype, sendbuf, recvbuf, op, size, ext, schedule, handle); break; } if (NBC_OK != res) { printf("Error in Schedule creation() (%i)\n", res); return res; } res = NBC_Sched_commit(schedule); if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Sched_commit() (%i)\n", res); return res; } #ifdef NBC_CACHE_SCHEDULE /* save schedule to tree */ args = (NBC_Allreduce_args*)malloc(sizeof(NBC_Allreduce_args)); args->sendbuf=sendbuf; args->recvbuf=recvbuf; args->count=count; args->datatype=datatype; args->op=op; args->schedule=schedule; res = hb_tree_insert ((hb_tree*)handle->comminfo->NBC_Dict[NBC_ALLREDUCE], args, args, 0); if(res != 0) printf("error in dict_insert() (%i)\n", res); /* increase number of elements for A2A */ if(++handle->comminfo->NBC_Dict_size[NBC_ALLREDUCE] > NBC_SCHED_DICT_UPPER) { NBC_SchedCache_dictwipe((hb_tree*)handle->comminfo->NBC_Dict[NBC_ALLREDUCE], &handle->comminfo->NBC_Dict_size[NBC_ALLREDUCE]); } } else { /* found schedule */ schedule=found->schedule; } #endif res = NBC_Start(handle, schedule); if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Start() (%i)\n", res); return res; } /* tmpbuf is freed with the handle */ return NBC_OK; } /* binomial allreduce (binomial tree up and binomial bcast down) * working principle: * - each node gets a virtual rank vrank * - the 'root' node get vrank 0 * - node 0 gets the vrank of the 'root' * - all other ranks stay identical (they do not matter) * * Algorithm: * pairwise exchange * round r: * grp = rank % 2^r * if grp == 0: receive from rank + 2^(r-1) if it exists and reduce value * if grp == 1: send to rank - 2^(r-1) and exit function * * do this for R=log_2(p) rounds * followed by a Bcast: * Algorithm: * - each node with vrank > 2^r and vrank < 2^r+1 receives from node * vrank - 2^r (vrank=1 receives from 0, vrank 0 receives never) * - each node sends each round r to node vrank + 2^r * - a node stops to send if 2^r > commsize * */ #define RANK2VRANK(rank, vrank, root) \ { \ vrank = rank; \ if (rank == 0) vrank = root; \ if (rank == root) vrank = 0; \ } #define VRANK2RANK(rank, vrank, root) \ { \ rank = vrank; \ if (vrank == 0) rank = root; \ if (vrank == root) rank = 0; \ } static inline int allred_sched_diss(int rank, int p, int count, MPI_Datatype datatype, void *sendbuf, void *recvbuf, MPI_Op op, NBC_Schedule *schedule, NBC_Handle *handle) { int root, vrank, r, maxr, firstred, vpeer, peer, res; root = 0; /* this makes the code for ireduce and iallreduce nearly identical - could be changed to improve performance */ RANK2VRANK(rank, vrank, root); maxr = (int)ceil((log((double)p)/LOG2)); firstred = 1; for(r=1; r<=maxr; r++) { if((vrank % (1<tmpbuf); printf("Error in NBC_Sched_recv() (%i)\n", res); return res; } /* we have to wait until we have the data */ res = NBC_Sched_barrier(schedule); if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Sched_barrier() (%i)\n", res); return res; } if(firstred && MPI_IN_PLACE != sendbuf) { /* perform the reduce with the senbuf */ res = NBC_Sched_op(recvbuf, false, sendbuf, false, 0, true, count, datatype, op, schedule); firstred = 0; } else { /* perform the reduce in my local buffer */ res = NBC_Sched_op(recvbuf, false, recvbuf, false, 0, true, count, datatype, op, schedule); } if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Sched_op() (%i)\n", res); return res; } /* this cannot be done until handle->tmpbuf is unused :-( */ res = NBC_Sched_barrier(schedule); if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Sched_barrier() (%i)\n", res); return res; } } } else { /* we have to send this round */ vpeer = vrank - (1<<(r-1)); VRANK2RANK(peer, vpeer, root) if(firstred && MPI_IN_PLACE != sendbuf) { /* we have to use the sendbuf in the first round .. */ res = NBC_Sched_send(sendbuf, false, count, datatype, peer, schedule); } else { /* and the recvbuf in all remeining rounds */ res = NBC_Sched_send(recvbuf, false, count, datatype, peer, schedule); } if(res != NBC_OK) { free(handle->tmpbuf); printf("Error in NBC_Sched_send() (%i)\n", res); return res; } /* leave the game */ break; } } /* this is the Bcast part - copied with minor changes from nbc_ibcast.c * changed: buffer -> recvbuf */ RANK2VRANK(rank, vrank, root); /* receive from the right hosts */ if(vrank != 0) { for(r=0; r= (1<tmpbuf); printf("Error in NBC_Sched_recv() (%i)\n", res); return res; } } } res = NBC_Sched_barrier(schedule); if(NBC_OK != res) { free(handle->tmpbuf); printf("Error in NBC_Sched_barrier() (%i)\n", res); return res; } } /* now send to the right hosts */ for(r=0; rtmpbuf); printf("Error in NBC_Sched_send() (%i)\n", res); return res; } } } /* end of the bcast */ return NBC_OK; } static inline int allred_sched_ring(int r, int p, int count, MPI_Datatype datatype, void *sendbuf, void *recvbuf, MPI_Op op, int size, int ext, NBC_Schedule *schedule, NBC_Handle *handle) { int i; /* runner */ int segsize, *segsizes, *segoffsets; /* segment sizes and offsets per segment (number of segments == number of nodes */ int speer, rpeer; /* send and recvpeer */ if(count == 0) return NBC_OK; { int mycount; /* temporary */ segsizes = (int*)malloc(sizeof(int)*p); segoffsets = (int*)malloc(sizeof(int)*p); segsize = count/p; /* size of the segments */ if(count%p != 0) segsize++; mycount = count; segoffsets[0] = 0; for(i = 0; i reduced this round * / -> sum (reduced in a previous step) * * *** round 0 *** * 0 1 2 * * 00 10 20 0: [1] -> 1 * 01 11 21 1: [2] -> 2 * 02 12 22 2: [0] -> 0 --> send element (r+1)%p to node (r+1)%p * * *** round 1 *** * 0 1 2 * * 00+20 10 20 0: red(0), [0] -> 1 * 01 11+01 21 1: red(1), [1] -> 2 * 02 12 22+12 2: red(2), [2] -> 0 --> reduce and send element (r+0)%p to node (r+1)%p * * *** round 2 *** * 0 1 2 * * 00/20 all 20 0: red(2), [2] -> 1 * 01 11/01 all 1: red(0), [0] -> 2 * all 12 22/12 2: red(1), [1] -> 0 --> reduce and send (r-1)%p to node (r+1)%p * * *** round 3 *** * 0 1 2 * * 00/20 all all 0: [1] -> 1 * all 11/01 all 1: [2] -> 2 * all all 22/12 2: [0] -> 0 --> send element (r-2)%p to node (r+1)%p * * *** round 4 *** * 0 1 2 * * all all all 0: done * all all all 1: done * all all all 2: done * * -> 4 * *** round 0 *** * 0 1 2 3 * * 00 10 20 30 0: [1] -> 1 * 01 11 21 31 1: [2] -> 2 * 02 12 22 32 2: [3] -> 3 * 03 13 23 33 3: [0] -> 0 --> send element (r+1)%p to node (r+1)%p * * *** round 1 *** * 0 1 2 3 * * 00+30 10 20 30 0: red(0), [0] -> 1 * 01 11+01 21 31 1: red(1), [1] -> 2 * 02 12 22+12 32 2: red(2), [2] -> 3 * 03 13 23 33+23 3: red(3), [3] -> 0 --> reduce and send element (r+0)%p to node (r+1)%p * * *** round 2 *** * 0 1 2 3 * * 00/30 10+00/30 20 30 0: red(3), [3] -> 1 * 01 11/01 21+11/01 31 1: red(0), [0] -> 2 * 02 12 22/12 32+22/12 2: red(1), [1] -> 3 * 03+33/23 13 23 33/23 3: red(2), [2] -> 0 --> reduce and send (r-1)%p to node (r+1)%p * * *** round 3 *** * 0 1 2 3 * * 00/30 10/00/30 all 30 0: red(2), [2] -> 1 * 01 11/01 21/11/01 all 1: red(3), [3] -> 2 * all 12 22/12 32/22/12 2: red(0), [0] -> 3 * 03/33/23 all 23 33/23 3: red(1), [1] -> 0 --> reduce and send (r-2)%p to node (r+1)%p * * *** round 4 *** * 0 1 2 3 * * 00/30 10/00/30 all all 0: [1] -> 1 * all 11/01 21/11/01 all 1: [2] -> 2 * all all 22/12 32/22/12 2: [3] -> 3 * 03/33/23 all all 33/23 3: [0] -> 0 --> receive and send element (r+1)%p to node (r+1)%p * * *** round 5 *** * 0 1 2 3 * * all 10/00/30 all all 0: [0] -> 1 * all all 21/11/01 all 1: [1] -> 2 * all all all 32/22/12 2: [3] -> 3 * 03/33/23 all all all 3: [4] -> 4 --> receive and send element (r-0)%p to node (r+1)%p * * *** round 6 *** * 0 1 2 3 * * all all all all * all all all all * all all all all * all all all all receive element (r-1)%p * * 2p-2 rounds ... every node does p-1 reductions and p-1 sends * */ { int round = 0; /* first p-1 rounds are reductions */ do { int selement = (r+1-round + 2*p /*2*p avoids negative mod*/)%p; /* the element I am sending */ int soffset = segoffsets[selement]*ext; int relement = (r-round + 2*p /*2*p avoids negative mod*/)%p; /* the element that I receive from my neighbor */ int roffset = segoffsets[relement]*ext; /* first message come out of sendbuf */ if(round == 0) { NBC_Sched_send((char*)sendbuf+soffset, false, segsizes[selement], datatype, speer, schedule); } else { NBC_Sched_send((char*)recvbuf+soffset, false, segsizes[selement], datatype, speer, schedule); } NBC_Sched_recv((char*)recvbuf+roffset, false, segsizes[relement], datatype, rpeer, schedule); NBC_Sched_barrier(schedule); NBC_Sched_op((char*)recvbuf+roffset, false, (char*)sendbuf+roffset, false, (char*)recvbuf+roffset, false, segsizes[relement], datatype, op, schedule); NBC_Sched_barrier(schedule); round++; } while(round < p-1); do { int selement = (r+1-round + 2*p /*2*p avoids negative mod*/)%p; /* the element I am sending */ int soffset = segoffsets[selement]*ext; int relement = (r-round + 2*p /*2*p avoids negative mod*/)%p; /* the element that I receive from my neighbor */ int roffset = segoffsets[relement]*ext; NBC_Sched_send((char*)recvbuf+soffset, false, segsizes[selement], datatype, speer, schedule); NBC_Sched_recv((char*)recvbuf+roffset, false, segsizes[relement], datatype, rpeer, schedule); NBC_Sched_barrier(schedule); round++; } while (round < 2*p-2); } return NBC_OK; }