MPI: Point-to-Point Communication

Listed below are MPI point-to-point communication times for a variety of message sizes. The total communication time is listed in terms of CPU clock cycles, and the bandwidth is listed in megabytes per second.

2 processors:

  CPU cycles per word for 1 word messages is 6817.500000 (0.04 Mbytes/sec)
  CPU cycles per word for 2 word messages is 3375.000000 (0.08 Mbytes/sec)
  CPU cycles per word for 4 word messages is 1738.125000 (0.16 Mbytes/sec)
  CPU cycles per word for 8 word messages is 885.937500 (0.30 Mbytes/sec)
  CPU cycles per word for 16 word messages is 451.406250 (0.60 Mbytes/sec)
  CPU cycles per word for 32 word messages is 232.031250 (1.16 Mbytes/sec)
  CPU cycles per word for 64 word messages is 157.148438 (1.72 Mbytes/sec)
  CPU cycles per word for 128 word messages is 92.285156 (2.93 Mbytes/sec)
  CPU cycles per word for 256 word messages is 59.853516 (4.51 Mbytes/sec)
  CPU cycles per word for 512 word messages is 43.374023 (6.22 Mbytes/sec)
  CPU cycles per word for 1024 word messages is 33.156738 (8.14 Mbytes/sec)
  CPU cycles per word for 2048 word messages is 32.563477 (8.29 Mbytes/sec)
  CPU cycles per word for 4096 word messages is 30.322266 (8.90 Mbytes/sec)
  CPU cycles per word for 8192 word messages is 25.427856 (10.62 Mbytes/sec)
  CPU cycles per word for 16384 word messages is 21.649933 (12.47 Mbytes/sec)
  CPU cycles per word for 32768 word messages is 19.079132 (14.15 Mbytes/sec)
  CPU cycles per word for 65536 word messages is 17.696915 (15.26 Mbytes/sec)
  CPU cycles per word for 131072 word messages is 16.991386 (15.89 Mbytes/sec)
  CPU cycles per word for 262144 word messages is 16.534338 (16.33 Mbytes/sec)
  CPU cycles per word for 524288 word messages is 16.583905 (16.28 Mbytes/sec)
  CPU cycles per word for 1048576 word messages is 16.448915 (16.41 Mbytes/sec)