[Simjoh]

I've my cases running nice and smooth as long as I run them one by one.

mpirun -np 2 interFoam -parallel >log.interFoam


But when I start multiple simulations from different case directories. I get all my jobs started on the very same processor ID. Each process then allocate 50% of the processor ID.

I guess it has to do with my mpi installation rather then with my openfoam installation. But I know a lot of you guys knows a lot about mpirun.

I followed this walktrough to install openfoam 3.0.1 on ubuntu 16.04
https://openfoamwiki.net/index.php/Installation/Linux/OpenFOAM-3.0.1/Ubuntu

Thanks for any help or pointer!

[Simjoh]

I kind of solved this problem with --cpu-set flag.

mpirun -np 2 --cpu-set 4-5 interFoam -parallel

I use a intel i7 5820k with 6 cores and hyperthreading turned off. If you use a quad core you would need to chang 4-5.


I think that mpirun should be able to to manage to do this by itself and is therefor not satisfied with my solution.

Hope someone finds this useful anyway.

/Simon

[xuegy]

Maybe you can try with '-bind-to core'. With that you can even turn on hyper threading without any trouble.

[Simjoh]

Thanks xuegy for your reply.
Will try your suggestion next time I'm at office.

About hyper threading I heard a lot about it being of no use together with open foam.

[Simjoh]

Originally Posted by xuegy

Maybe you can try with '-bind-to core'. With that you can even turn on hyper threading without any trouble.

Tanks for the input but it didn't help. I'll stick to declaring processor myself until i get some other working suggestions..

[thiagopl]

Hi all,

For those who ended up here I recommend this material about running OpenFOAM in parallel which approachs the hyperthreading issues.

Module 4 | Running in parallel #openfoamtraining
http://www.wolfdynamics.com/wiki/parallel.pdf
At the playlist below you can see the videos of Module 4.
https://www.youtube.com/playlist?lis...mDChejiwm846Wl

Hope it helps.

Regards.