84 строки
2.6 KiB
C
84 строки
2.6 KiB
C
/*
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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* Copyright (c) 2004-2006 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2006 Cisco Systems, Inc. All rights reserved.
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* $COPYRIGHT$
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*
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* Additional copyrights may follow
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*
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* $HEADER$
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*/
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#include "ompi_config.h"
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#include <stdlib.h>
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#include "ompi/mca/pml/pml.h"
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#include "ompi/communicator/communicator.h"
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#include "ompi/request/request.h"
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#include "ompi/runtime/mpiruntime.h"
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/*
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* do zero byte IRECV / ISEND: upper half sends to lower half (i.e. do
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* a ping, not a ping pong)
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*/
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int ompi_init_do_preconnect(void)
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{
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int comm_size = ompi_comm_size(MPI_COMM_WORLD);
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int my_rank = ompi_comm_rank(MPI_COMM_WORLD);
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int i, ret;
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int next,prev;
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struct ompi_request_t * requests[2];
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ret = OMPI_SUCCESS;
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if(comm_size == 2) {
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if(my_rank){
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ret = MCA_PML_CALL(send(MPI_BOTTOM, 0, MPI_BYTE,
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0, 1,
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MCA_PML_BASE_SEND_COMPLETE,
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MPI_COMM_WORLD));
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if(OMPI_SUCCESS != ret) {
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return ret;
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}
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} else {
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ret = MCA_PML_CALL(recv(MPI_BOTTOM,0, MPI_BYTE, 1,
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1, MPI_COMM_WORLD,
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MPI_STATUS_IGNORE));
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if(OMPI_SUCCESS != ret) {
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return ret;
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}
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}
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} else {
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for (i = 1; i <= comm_size/2; ++i) {
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next = (my_rank + i) % comm_size;
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prev = (my_rank - i + comm_size) % comm_size;
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ret = MCA_PML_CALL(irecv(MPI_BOTTOM,0, MPI_BYTE,
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prev, 1,
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MPI_COMM_WORLD,
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&requests[0]));
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if(OMPI_SUCCESS != ret) {
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return ret;
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}
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ret = MCA_PML_CALL(isend(MPI_BOTTOM, 0, MPI_BYTE,
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next, 1,
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MCA_PML_BASE_SEND_STANDARD,
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MPI_COMM_WORLD,
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&requests[1]));
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if (OMPI_SUCCESS != ret) {
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return ret;
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}
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ret = ompi_request_wait_all(2, requests, MPI_STATUSES_IGNORE);
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if (OMPI_SUCCESS != ret) {
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return ret;
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}
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}
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}
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return ret;
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}
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