3 Environment Variables

The environment variables which beginning with OMP_ are defined by section 4 of the OpenMP specification in version 4.0, while those beginning with GOMP_ are GNU extensions.

• OMP_CANCELLATION: Set whether cancellation is activated
• OMP_DISPLAY_ENV: Show OpenMP version and environment variables
• OMP_DEFAULT_DEVICE: Set the device used in target regions
• OMP_DYNAMIC: Dynamic adjustment of threads
• OMP_MAX_ACTIVE_LEVELS: Set the maximum number of nested parallel regions
• OMP_NESTED: Nested parallel regions
• OMP_NUM_THREADS: Specifies the number of threads to use
• OMP_PROC_BIND: Whether theads may be moved between CPUs
• OMP_PLACES: Specifies on which CPUs the theads should be placed
• OMP_STACKSIZE: Set default thread stack size
• OMP_SCHEDULE: How threads are scheduled
• OMP_THREAD_LIMIT: Set the maximum number of threads
• OMP_WAIT_POLICY: How waiting threads are handled
• GOMP_CPU_AFFINITY: Bind threads to specific CPUs
• GOMP_DEBUG: Enable debugging output
• GOMP_STACKSIZE: Set default thread stack size
• GOMP_SPINCOUNT: Set the busy-wait spin count