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-   -   Problem with mpirun with OpenFOAM (http://www.cfd-online.com/Forums/openfoam/77897-problem-mpirun-openfoam.html)

jiejie July 7, 2010 05:19

Problem with mpirun with OpenFOAM
 
Recently I am having a strange problem with mpirun in OpenFOAM 1.6. I am running 3D LES of flow over a cylinder. I have 17 nodes (16 cells) in the spanwise direction (z-direction).

When I did a very coarse mesh (7500 cells per plane) in the xy plane, i can decompose the domain into 8 portions in the z-direction and run without any problem.

When I did fine mesh (120,000 cells per plane) in the xy plane, I decompose the domain into 8 portions in the z-direction. After I executed the mpirun -np 8 pisoFoam -parallel, it complains the followings:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0

[shuang:8030] *** An error occurred in MPI_Bsend
[shuang:8030] *** on communicator MPI_COMM_WORLD
[shuang:8030] *** MPI_ERR_BUFFER: invalid buffer pointer
[shuang:8030] *** MPI_ERRORS_ARE_FATAL (your MPI job will now abort)
--------------------------------------------------------------------------
mpirun has exited due to process rank 0 with PID 8030 on
node shuang exiting without calling "finalize". This may
have caused other processes in the application to be
terminated by signals sent by mpirun (as reported here).
--------------------------------------------------------------------------
[shuang:08029] 1 more process has sent help message help-mpi-errors.txt / mpi_errors_are_fatal
[shuang:08029] Set MCA parameter "orte_base_help_aggregate" to 0 to see all help / error messages


Then I decompose it into 2 portions along each the x, y (2 2 2 ) direction. It runs without this problem. If I wanna run the simulaiton with 8 portions along z-direction, what should I fix?

Does anyone encounter such a problem as well?

sbar July 7, 2010 05:37

Hi,
I have the same problem. I'm running a simpleFoam simulation on an 8 core Workstation. I decomposed the mesh in 8 parts in x direction. The error doesn't appear every time. I read in another forum that there was/is a bug in openMpi that should be fixed. something about restarting checkpoints.

would be great if someone could help.

thekay July 7, 2010 09:17

You need to raise the mpi buffer size. This can be done by running something like:
Code:

MPI_BUFFER_SIZE=150000000
. Normally you'd like to put it in your settings file so you don't have to run it each time.

jiejie July 7, 2010 19:30

Quote:

Originally Posted by thekay (Post 266178)
You need to raise the mpi buffer size. This can be done by running something like:
Code:

MPI_BUFFER_SIZE=150000000
. Normally you'd like to put it in your settings file so you don't have to run it each time.

Thanks thekay

it works well after I increase the buffer size.


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