mpirun start second run on same processor as the already running

Simjoh · November 2, 2016, 08:40

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 · November 2, 2016, 09:58

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 · November 3, 2016, 13:07

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

Simjoh · November 3, 2016, 13:46

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 · November 9, 2016, 02:59

Quote:

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..

November 2, 2016, 08:40	mpirun start second run on same processor as the already running	#1
Simjoh New Member Simon Johansson Join Date: Sep 2011 Posts: 15 Rep Power: 13	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!

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November 2, 2016, 09:58		#2
Simjoh New Member Simon Johansson Join Date: Sep 2011 Posts: 15 Rep Power: 13	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

November 3, 2016, 13:07		#3
xuegy Member Join Date: Jun 2016 Posts: 97 Rep Power: 8	Maybe you can try with '-bind-to core'. With that you can even turn on hyper threading without any trouble.

November 3, 2016, 13:46		#4
Simjoh New Member Simon Johansson Join Date: Sep 2011 Posts: 15 Rep Power: 13	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.