Hi Na Zhang, It seems likely that on your Open MPI 1.8.1 run that you have the 2 ranks running on one host whereas on the 1.6.5 results they are running on 2 hosts. You should be able to verify that by running top on one of the nodes during the 1.8.1 runs and see if you have 2 or 0 osu_latency processes running on that node.
Also, it would be useful to see your mpirun or other launch command for your job for both MPI versions. Thanks, Tom From: users [mailto:users-boun...@open-mpi.org] On Behalf Of Na Zhang Sent: Tuesday, July 15, 2014 11:01 AM To: us...@open-mpi.org Subject: Re: [OMPI users] Running OSU benchmark latency test with Open MPI version 1.6.5 and version 1.8.1 Forgot to add the config info about the tests in previous post. We have FDR IB, two nodes (HP DL 380 G8 sever) communicating through a Mellanox Switch, RDMA mode, hyperthreading enabled. Thanks, Na Zhang On Tue, Jul 15, 2014 at 12:00 PM, Na Zhang <nkuzhan...@gmail.com<mailto:nkuzhan...@gmail.com>> wrote: Dear developers and users, I am trying to run OSU benchmark tests (like osu_latency, osu_bw, etc) with Open MPI. While I was able to run the tests with both versions (1.6.5, 1.8.1, same default build), I got disparate performance results. Please see data below. I wonder what reason would cause the performance difference. And also, I was trying to run the tests with latest release 1.8.2, got the warning like below, and got the results similar to version 1.8.1. How can I avoid this warning? -------------------------------------------------------------------------- WARNING: a request was made to bind a process. While the system supports binding the process itself, at least one node does NOT support binding memory to the process location. Node: hostname This is a warning only; your job will continue, though performance may be degraded. -------------------------------------------------------------------------- Thanks, Na Zhang Version 1.6.5 # OSU MPI Latency Test v4.3 # Size Latency (us) 0 1.83 1 1.11 2 1.11 4 1.11 8 1.13 16 1.15 32 1.17 64 1.22 128 1.54 256 1.73 512 1.90 1024 2.24 2048 2.93 4096 3.59 8192 4.96 16384 7.81 32768 11.22 65536 18.18 131072 32.10 262144 59.91 524288 115.56 1048576 226.84 2097152 449.71 4194304 894.75 Version 1.8.1 # OSU MPI Latency Test v4.3 # Size Latency (us) 0 0.22 1 0.27 2 0.27 4 0.27 8 0.27 16 0.28 32 0.28 64 0.31 128 0.44 256 0.47 512 0.48 1024 0.60 2048 0.83 4096 1.30 8192 1.95 16384 3.45 32768 5.79 65536 8.88 131072 15.79 262144 28.78 524288 53.50 1048576 104.09 2097152 202.54 4194304 398.43
