Intel® MPI Benchmarks User Guide and Methodology Description

# Sample 1 - IMB-MPI1 PingPong Allreduce

The following example shows the results of the `PingPong` and `Allreduce` benchmark:

    <..>  np 2 IMB-MPI1 PingPong Allreduce
    #---------------------------------------------------
    # Intel ® MPI Benchmark Suite V3.2, MPI1 part
    #---------------------------------------------------
    # Date                  : Thu Sep  4 13:20:07 2008
    #  Machine               : x86_64
    #  System                : Linux
    #  Release               : 2.6.9-42.ELsmp
    #  Version               : #1 SMP Wed Jul 12 23:32:02 EDT 2006
    #  MPI Version           : 2.0
    #  MPI Thread Environment: MPI_THREAD_SINGLE

    #  New default behavior from Version 3.2 on:
    #  the number of iterations per message size is cut down
    # dynamically when a certain run time (per message size sample)
    # is expected to be exceeded. Time limit is defined by variable
    #  SECS_PER_SAMPLE (=> IMB_settings.h)
    #  or through the flag => -time

    #  Calling sequence was:

    #  ./IMB-MPI1 PingPong Allreduce

    #  Minimum message length in bytes:   0
    #  Maximum message length in bytes:   4194304
    #
    #  MPI_Datatype                   :   MPI_BYTE
    #  MPI_Datatype for reductions    :   MPI_FLOAT
    #  MPI_Op                         :   MPI_SUM
    #
    #

    #  List of Benchmarks to run:

    #  PingPong
    #  Allreduce

    #---------------------------------------------------
    #  Benchmarking PingPong
    #  #processes = 2
    #---------------------------------------------------
     #bytes  #repetitions      t[μsec]   Mbytes/sec
          0         1000         ..       ..
          1         1000
          2         1000
          4         1000
          8         1000
         16         1000
         32         1000
         64         1000
        128         1000
        256         1000
        512         1000
       1024         1000
       2048         1000
       4096         1000
       8192         1000
      16384         1000
      32768         1000
      65536          640
     131072          320
     262144          160
     524288           80
    1048576           40
    2097152           20
    4194304           10
    #-------------------------------------------------------
    #  Benchmarking Allreduce
    #  ( #processes = 2 )
    #-------------------------------------------------------
     #bytes  #repetitions  t_min[μsec]  t_max[μsec]   t_avg[μsec]
          0         1000         ..          ..          ..
          4         1000
          8         1000
         16         1000
         32         1000
         64         1000
        128         1000
        256         1000
        512         1000
       1024         1000
       2048         1000
       4096         1000
       8192         1000
      16384         1000
      32768         1000
      65536          640
     131072          320
     262144          160
     524288           80
    1048576           40
    2097152           20
    4194304           10

    # All processes entering MPI_Finalize