The XLSMPOPTS environment variable sets options for program run time using loop parallelization. Suboptions for the XLSMPOPTS environment variables are discussed in detail in XLSMPOPTS.
If you are using OpenMP constucts for parallelization, you can also specify runtime options using OMP environment variables, as discussed in OpenMP environment variables for parallel processing.
When runtime options specified by OMP and XLSMPOPTS environment variables conflict, OMP options will prevail.