src/gromacs/utility/basenetwork.cpp

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  38 #include "gmxpre.h"
  39
  40 #include "basenetwork.h"
  41
  42 #include "config.h"
  43
  44 #include <climits>
  45 #include <cstdio>
  46 #include <cstdlib>
  47 #include <cstring>
  48
  49 #include "gromacs/utility/cstringutil.h"
  50 #include "gromacs/utility/fatalerror.h"
  51 #include "gromacs/utility/gmxmpi.h"
  52
  53 bool gmx_mpi_initialized()
  54 {
  55 #if !GMX_MPI
  56     return false;
  57 #else
  58     int n;
  59     MPI_Initialized(&n);
  60
  61     return n != 0;
  62 #endif
  63 }
  64
  65 int gmx_node_num()
  66 {
  67 #if !GMX_MPI
  68     return 1;
  69 #else
  70 #    if GMX_THREAD_MPI
  71     if (!gmx_mpi_initialized())
  72     {
  73         return 1;
  74     }
  75 #    endif
  76     int i;
  77     (void)MPI_Comm_size(MPI_COMM_WORLD, &i);
  78     return i;
  79 #endif
  80 }
  81
  82 int gmx_node_rank()
  83 {
  84 #if !GMX_MPI
  85     return 0;
  86 #else
  87 #    if GMX_THREAD_MPI
  88     if (!gmx_mpi_initialized())
  89     {
  90         return 0;
  91     }
  92 #    endif
  93     int i;
  94     (void)MPI_Comm_rank(MPI_COMM_WORLD, &i);
  95     return i;
  96 #endif
  97 }
  98
  99 static int mpi_hostname_hash()
 100 {
 101     int hash_int;
 102
 103 #if GMX_LIB_MPI
 104     int  resultlen;
 105     char mpi_hostname[MPI_MAX_PROCESSOR_NAME];
 106
 107     /* This procedure can only differentiate nodes with different names.
 108      * Architectures where different physical nodes have identical names,
 109      * such as IBM Blue Gene, should use an architecture specific solution.
 110      */
 111     MPI_Get_processor_name(mpi_hostname, &resultlen);
 112
 113     /* The string hash function returns an unsigned int. We cast to an int.
 114      * Negative numbers are converted to positive by setting the sign bit to 0.
 115      * This makes the hash one bit smaller.
 116      * A 63-bit hash (with 64-bit int) should be enough for unique node hashes,
 117      * even on a million node machine. 31 bits might not be enough though!
 118      */
 119     hash_int = static_cast<int>(gmx_string_fullhash_func(mpi_hostname, gmx_string_hash_init));
 120     if (hash_int < 0)
 121     {
 122         hash_int -= INT_MIN;
 123     }
 124 #else
 125
 126     /* thread-MPI currently puts the thread number in the process name,
 127      * we might want to change this, as this is inconsistent with what
 128      * most MPI implementations would do when running on a single node.
 129      */
 130     hash_int = 0;
 131 #endif
 132
 133     return hash_int;
 134 }
 135
 136 int gmx_physicalnode_id_hash()
 137 {
 138     int hash = 0;
 139
 140     if (GMX_MPI)
 141     {
 142         hash = mpi_hostname_hash();
 143     }
 144
 145     if (debug)
 146     {
 147         fprintf(debug, "In gmx_physicalnode_id_hash: hash %d\n", hash);
 148     }
 149
 150     return hash;
 151 }
 152
 153 void gmx_broadcast_world(int size, void* buffer)
 154 {
 155 #if GMX_MPI
 156     MPI_Bcast(buffer, size, MPI_BYTE, 0, MPI_COMM_WORLD);
 157 #else
 158     GMX_UNUSED_VALUE(size);
 159     GMX_UNUSED_VALUE(buffer);
 160 #endif
 161 }
 162
 163 #if GMX_LIB_MPI
 164 void gmx_abort(int errorno)
 165 {
 166     MPI_Abort(MPI_COMM_WORLD, errorno);
 167     std::abort();
 168 }
 169 #endif