Tips & Tricks - chaos-polymtl/lethe GitHub Wiki
Disabling shared-memory parallelism of Trilinos
By default, Trilinos is often compiled with openmp enabled. Regretfully, this more often than not leads to very poor parallel peformance. Shared memory parallelism in Trilinos can be either disabled at compile time, or disabled from the terminal. To disable it from the terminal, the number of OpenMP threads can be forcefully set to 1 by setting the OMP_NUM_THREADS
environment variable.
This can be done by adding the following line to your $HOME/.bashrc
file:
export OMP_NUM_THREADS=1