% mpicc -o memcpy memcpy.c % mpirun -np 1 memcpy Size (bytes) Time (sec) Rate (MB/sec) 4 0.000001 4.647218 8 0.000001 5.601300 16 0.000002 10.177081 32 0.000002 17.395842 64 0.000003 25.467974 128 0.000004 33.239156 256 0.000007 39.369105 512 0.000012 43.057177 1024 0.000023 45.335452 2048 0.000045 45.320018 4096 0.000324 12.631927 8192 0.000279 29.386145 16384 0.000553 29.605180 32768 0.001106 29.631952 65536 0.002214 29.598495 131072 0.004425 29.618560 262144 0.008847 29.630835 524288 0.017676 29.661009 1048576 0.035314 29.692926 2097152 0.070625 29.694188