Techniques to Set the Number of Threads
Use the following techniques to specify the number of threads to use in Intel MKL:
- Set one of the OpenMP or Intel MKL environment variables:
- Call one of the OpenMP or Intel MKL functions:
When choosing the appropriate technique, take into account the following rules:
- The Intel MKL threading controls take precedence over the OpenMP controls because they are inspected first.
- A function call takes precedence over any environment settings. The exception, which is a consequence of the previous rule, is that a call to the OpenMP subroutine
omp_set_num_threads() does not have precedence over the settings of Intel MKL environment variables such as
MKL_NUM_THREADS. See Using Additional Threading Control for more details.
- You cannot change run-time behavior in the course of the run using the environment variables because they are read only once at the first call to Intel MKL.