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‎Makefile

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###############################################################################
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# Copyright (c) 2010-2012 Los Alamos National Security, LLC.
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# All rights reserved.
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#
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# This program was prepared by Los Alamos National Security, LLC at Los Alamos
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# National Laboratory (LANL) under contract No. DE-AC52-06NA25396 with the U.S.
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# Department of Energy (DOE). All rights in the program are reserved by the DOE
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# and Los Alamos National Security, LLC. Permission is granted to the public to
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# copy and use this software without charge, provided that this Notice and any
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# statement of authorship are reproduced on all copies. Neither the U.S.
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# Government nor LANS makes any warranty, express or implied, or assumes any
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# liability or responsibility for the use of this software.
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################################################################################
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TARGET = mpi-smp-comm
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SHELL = /bin/sh
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CC = mpicc
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CFLAGS = -Wall
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.SUFFIXES:
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.SUFFIXES: .c .o
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.PHONY: clean all
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all: ${TARGET}
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clean:
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/bin/rm -f ${TARGET}

‎README

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###############################################################################
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mpi-smp-comm
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###############################################################################
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One way of determining the amount of local processes on a node using MPI 2.

‎mpi-smp-comm.c

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/**
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* Copyright (c) 2010-2012 Los Alamos National Security, LLC.
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* All rights reserved.
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*
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* This program was prepared by Los Alamos National Security, LLC at Los Alamos
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* National Laboratory (LANL) under contract No. DE-AC52-06NA25396 with the U.S.
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* Department of Energy (DOE). All rights in the program are reserved by the DOE
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* and Los Alamos National Security, LLC. Permission is granted to the public to
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* copy and use this software without charge, provided that this Notice and any
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* statement of authorship are reproduced on all copies. Neither the U.S.
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* Government nor LANS makes any warranty, express or implied, or assumes any
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* liability or responsibility for the use of this software.
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*/
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/**
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* @author Samuel K. Gutierrez
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*/
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/* /////////////////////////////////////////////////////////////////////////////
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o CHANGE LOG
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2010-11-05 Samuel K. Gutierrez
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* initial implementation.
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2010-11-08 Samuel K. Gutierrez
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* updated algorithm - last version didn't work.
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2011-04-22 Samuel K. Gutierrez
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* updated macros.
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2012-10-10 Samuel K. Gutierrez
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* updates for release.
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///////////////////////////////////////////////////////////////////////////// */
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdint.h>
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#include <netdb.h>
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#include <arpa/inet.h>
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#include "mpi.h"
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/* application name */
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#define SMPCOMM_NAME "mpi-smp-comm"
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/* current version */
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#define SMPCOMM_VER "0.0.5"
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/* ////////////////////////////////////////////////////////////////////////// */
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/* convenience macros */
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/* ////////////////////////////////////////////////////////////////////////// */
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/* "master" rank */
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#define SMPCOMM_MASTER_RANK 0
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#define SMPCOMM_FAILURE 0
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#define SMPCOMM_SUCCESS 1
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#define SMPCOMM_STRINGIFY(x) #x
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#define SMPCOMM_TOSTRING(x) SMPCOMM_STRINGIFY(x)
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#define SMPCOMM_ERR_AT __FILE__ " ("SMPCOMM_TOSTRING(__LINE__)")"
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#define SMPCOMM_ERR_PREFIX "-[SMPCOMM ERROR: "SMPCOMM_ERR_AT"]- "
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/* error message */
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#define SMPCOMM_ERR_MSG(pfargs...) \
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do { \
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fprintf(stderr, SMPCOMM_ERR_PREFIX); \
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fprintf(stderr, pfargs); \
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} while (0)
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/* mpi check */
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#define SMPCOMM_MPICHK(_ret_,_gt_) \
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do { \
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if (MPI_SUCCESS != (_ret_)) { \
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MPI_Error_string((_ret_), \
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err_str, \
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&err_str_len); \
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SMPCOMM_ERR_MSG("mpi success not returned on %s... %s (errno: %d)\n", \
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host_name_buff, \
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err_str, \
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(_ret_)); \
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goto _gt_; \
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} \
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} while (0)
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/* printf with flush */
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#define SMPCOMM_PF(pfargs...) \
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do { \
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fprintf(stdout, pfargs); \
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fflush(stdout); \
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} while (0)
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/* master rank printf */
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/* master rank printf */
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#define SMPCOMM_MPF(pfargs...) \
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do { \
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if (my_rank == (SMPCOMM_MASTER_RANK)) { \
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fprintf(stdout, pfargs); \
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fflush(stdout); \
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} \
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} while (0)
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/* memory alloc check */
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#define SMPCOMM_MEMCHK(_ptr_,_gt_) \
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do { \
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if (NULL == (_ptr_)) { \
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SMPCOMM_ERR_MSG("memory allocation error on %s\n", host_name_buff); \
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goto _gt_; \
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} \
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} while (0)
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/* error string length */
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static int err_str_len;
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/* error string buffer */
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static char err_str[MPI_MAX_ERROR_STRING];
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/* host name buffer */
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static char host_name_buff[MPI_MAX_PROCESSOR_NAME];
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/* ////////////////////////////////////////////////////////////////////////// */
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/* static forward declarations */
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/* ////////////////////////////////////////////////////////////////////////// */
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/* ////////////////////////////////////////////////////////////////////////// */
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/* helper functions */
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/* ////////////////////////////////////////////////////////////////////////// */
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/* ////////////////////////////////////////////////////////////////////////// */
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static int
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get_net_num(char *hstn,
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unsigned long int *net_num)
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{
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struct hostent *host = NULL;
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if (NULL == (host = gethostbyname(hstn))) {
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SMPCOMM_ERR_MSG("gethostbyname error\n");
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/* epic fail! */
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goto err;
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}
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/* htonl used here because nodes could be different architectures */
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*net_num = htonl(inet_network(inet_ntoa(*(struct in_addr *)host->h_addr)));
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return SMPCOMM_SUCCESS;
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err:
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return SMPCOMM_FAILURE;
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}
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/* ////////////////////////////////////////////////////////////////////////// */
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static int
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cmp_uli(const void *p1,
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const void *p2)
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{
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return (*(unsigned long int *)p1 - *(unsigned long int *)p2);
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}
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/* ////////////////////////////////////////////////////////////////////////// */
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static void
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get_my_color(unsigned long int *net_nums /* in */,
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int net_num_len /* in */,
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const unsigned long int *my_net_num /* in */,
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int *my_color /* out */)
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{
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int i = 0;
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int node_i = 0;
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unsigned long int prev_num;
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qsort(net_nums, (size_t)net_num_len, sizeof(unsigned long int), cmp_uli);
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prev_num = net_nums[0];
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while (i < net_num_len && prev_num != *my_net_num) {
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while (net_nums[i] == prev_num) {
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++i;
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}
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++node_i;
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prev_num = net_nums[i];
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}
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*my_color = node_i;
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}
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/* ////////////////////////////////////////////////////////////////////////// */
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/* main */
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/* ////////////////////////////////////////////////////////////////////////// */
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int
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main(int argc,
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char **argv)
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{
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/* pointer to array that holds net nums for all rank processes */
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unsigned long int *net_nums = NULL;
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/* my color */
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int my_color;
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/* my rank */
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int my_rank;
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/* size of mpi_comm_world */
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int num_ranks;
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/* hostname length */
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int hostname_len;
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/* local rank communicator */
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MPI_Comm local_comm;
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/* holds mpi return codes */
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int mpi_ret_code;
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/* number of local ranks */
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int num_local_procs;
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/* my local rank number */
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int my_local_rank;
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unsigned long int net_num;
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/* init MPI */
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mpi_ret_code = MPI_Init(&argc, &argv);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get comm size */
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mpi_ret_code = MPI_Comm_size(MPI_COMM_WORLD, &num_ranks);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get my rank */
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mpi_ret_code = MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get my host's name */
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mpi_ret_code = MPI_Get_processor_name(host_name_buff, &hostname_len);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get my network number */
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if (SMPCOMM_SUCCESS != get_net_num(host_name_buff, &net_num)) {
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goto error;
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}
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net_nums = (unsigned long int *)malloc(sizeof(unsigned long int) *
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num_ranks);
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SMPCOMM_MEMCHK(net_nums, error);
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/* get everyone else's net_num value */
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mpi_ret_code = MPI_Allgather(&net_num,
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1,
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MPI_UNSIGNED_LONG,
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net_nums,
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1,
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MPI_UNSIGNED_LONG,
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MPI_COMM_WORLD);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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get_my_color(net_nums, num_ranks, &net_num, &my_color);
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/* free up some resources - no longer needed */
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free(net_nums);
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/* split into local node groups */
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mpi_ret_code = MPI_Comm_split(MPI_COMM_WORLD,
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my_color,
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my_rank,
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&local_comm);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get local comm size */
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mpi_ret_code = MPI_Comm_size(local_comm, &num_local_procs);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* get my local comm rank */
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mpi_ret_code = MPI_Comm_rank(local_comm, &my_local_rank);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* let the "master process" print out some header stuff */
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SMPCOMM_MPF("# %s %s\n", SMPCOMM_NAME, SMPCOMM_VER);
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SMPCOMM_MPF("# numpe %d\n", num_ranks);
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/**
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* not needed... just used to make sure that the
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* header stuff is flushed before following info
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*/
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MPI_Barrier(MPI_COMM_WORLD);
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if (0 == my_local_rank) {
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SMPCOMM_PF("# host %s has %d local rank process%s\n",
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host_name_buff,
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num_local_procs,
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num_local_procs> 1 && 0 != num_local_procs ? "es ":" ");
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}
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mpi_ret_code = MPI_Comm_free(&local_comm);
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SMPCOMM_MPICHK(mpi_ret_code, error);
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/* done! */
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mpi_ret_code = MPI_Finalize();
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SMPCOMM_MPICHK(mpi_ret_code, error);
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return EXIT_SUCCESS;
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error:
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MPI_Abort(MPI_COMM_WORLD, mpi_ret_code);
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return EXIT_FAILURE;
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}

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