Using multiple cores not working in Ubuntu 14.04

Discussion about building and installing Elmer
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DePurpereWolf
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Using multiple cores not working in Ubuntu 14.04

Post by DePurpereWolf »

Hello,

I have updated one of the pc's here to Ubuntu 14.04 and reinstalled Elmer. It doesn't seem to be using multiple cores.

I have certain computations that do not use partitioning of the mesh. In the past I was able to run this simulation on multiple cores using mpirun. This is still the case on my laptop which also runs 14.04 (but a different install of Elmer)

When I try to execute the same simulation on the desktop, it halts with the message that it can't find a partitioned mesh (partition.3/part.3.header) However, I am not using a partitioned mesh.

I can execute the simulation without mpirun, then it uses one core and takes forever to finish.

Is this a setting in Elmer that I've missed? Or did something go wrong in the install.
raback
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Re: Using multiple cores not working in Ubuntu 14.04

Post by raback »

Hi

To my knowledge there has never been a MPI version of Elmer which would not require mesh partitioning.

There are strategies under development to utilize multiple cores using OpenMP without need of partitioning but this is under work, and is not related to MPI parallelization.

-Peter
DePurpereWolf
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Re: Using multiple cores not working in Ubuntu 14.04

Post by DePurpereWolf »

I see I have just been running multiple commands at the same time instead of spreading the load.
So there was no time win at all.

At least now an error message is shown.

Sorry for taking your time with my wishful thinking.
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