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Subject: Re: [OMPI users] OpenMPI 1.8.1 runs more OpenMP Threads on the same core
From: Ralph Castain (rhc.openmpi_at_[hidden])
Date: 2014-06-27 06:30:09

You should add this to your cmd line:

--map-by core:pe=4

This will bind each process to 4 cores

Sent from my iPhone

> On Jun 27, 2014, at 5:22 AM, Luigi Santangelo <luigi.santangelo_at_[hidden]> wrote:
> 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
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