Hello,
I'm running OpenMPI 1.8.5 on a cluster with the following characteristics:
Each node is equipped with two Intel Xeon E5-2630v3 processors (with 8
cores each), 128 GB of RAM and a 10 Gigabit Ethernet adapter.
When I run the NAS benchmarks using 8 cores in the same machine, I'm
getting almost the same performance as using 8 machines running a mpi
process per machine.
I used the following commands:
for running multi-node:
mpirun -np 8 --machinefile machine_file.txt --mca btl self,sm,tcp
--allow-run-as-root mg.C.8
for running in with 8 cores:
mpirun -np 8 --mca btl self,sm,tcp --allow-run-as-root mg.C.8
I got the following results:
8 cores:
Mop/s total = 19368.43
8 machines:
Mop/s total = 19326.60
The results are similar for other benchmarks. Is this behavior normal? I
was expecting to see a better behavior using 8 cores given that they use
directly the memory to communicate.
Thank you,
Cristian
