[mvapich-discuss] question regarding threaded application

[Alan Souza]

I have an application that make heavy use of some multi threaded 
libraries (openblas, the library was compiled to use OPENMP and with no 
thread binding) and umfpack. All communications are realized from 
the main thread (I already have tested some variations of 
MPI_Init_thread), B ut when I use the mvapich occurs some problems. On 
the cluster that I using each node has 8 cores and I am using only one 
MPI process per node.

But
 when I was observing the process on some nodes I have noticed that was 
created 9 threads (one of them is keep active only on some serial parts 
and the others inactive. In the explicit threaded (using openMP) parts of the 
application eight threads are active and this one stays idle). The main 
problem with this to me is the increase of memory
 comsuption, because some allocations are done before the threeaded parts... . This behavior doesn't occur  neither using mpich nor 
OpenMPI.

I use the following command to launch the jobs when using mvapich 2.0rc1:

mpirun_rsh
 -np ${N} -hostfile host.txt MV2_ENABLE_AFFINITY=0 MV2_IBA_HCA=mlx4_0 
MV2_NUM_HCAS=1 OMP_NUM_THREADS=8 ./application parameters

The hostfile contains the name of each node used and using the extended syntax :1 to indicate the number of processes per node.


thanks
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