Dear Colleague Hi I am working on hybrid MPI -OpenMp code and face with a problem. I can not run the code as the way that I want. I can run pure mpi code and also pure openmp code, but not hybrid one. I used "export OMP_NUM_THREADS=6" and then "mpirun -np 4 ./hybrid.exe > output.txt" It run but I noticed that It used only virtual threads of CPUs not physical threads. I have both OpenMpi and Mpich on my computer. My problem is I want to use mpi for communication between nodes and sockets and Openmp for cores which are inside of sockets and nodes, I do not know how to pin cpu to each other in each socket and nodes. I could find some material on internet such as https://aciref.org/how-to-gain-hybrid-mpi-openmp-code-performance-without-ch... How to gain hybrid MPI-OpenMP code performance without ...<https://aciref.org/how-to-gain-hybrid-mpi-openmp-code-performance-without-changing-a-line-of-code-a-k-a-dealing-with-task-affinity/> aciref.org How to gain hybrid MPI-OpenMP code performance without changing a line of code a.k.a. dealing with task affinity But it did not work, I think I need a PBS file to assign those commands on my grid with qsub command. If you need more information please let me know. I am looking forward to hearing from you, Best regards. Pasha Pashaei _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss