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Subject: [OMPI users] OpenMPI 1.8.1 runs more OpenMP Threads on the same core
From: Luigi Santangelo (luigi.santangelo_at_[hidden])
Date: 2014-06-27 06:22:27


Hi all,
My system is a 64 core, with Debian 3.2.57 64 bit, GNU gcc 4.7, kernel
Linux 3.2.0 and OpenMPI 1.8.1.
I developed an application to matching proteins files using OpenMP+OpenMPI.
I compiled souce code with -fopenmp flag, I set OMP_NUM_THREADS=4 then I
ran binary with mpiexec -np 16.
When the program runs, the top command show me that only 16 core are used.
If I use the previous of OpenMPI (1.6.5) it works fine. Must I set anything
in the new version? Where I wrong?

Thanks in advance

Luigi