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4 OpenMP Environment Variables ¶

The environment variables which beginning with OMP_ are defined by section 4 of the OpenMP specification in version 4.5, 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_MAX_TASK_PRIORITY – Set the maximum priority
• OMP_NESTED – Nested parallel regions
• OMP_NUM_TEAMS – Specifies the number of teams to use by teams region
• OMP_NUM_THREADS – Specifies the number of threads to use
• OMP_PROC_BIND – Whether threads may be moved between CPUs
• OMP_PLACES – Specifies on which CPUs the threads should be placed
• OMP_STACKSIZE – Set default thread stack size
• OMP_SCHEDULE – How threads are scheduled
• OMP_TARGET_OFFLOAD – Controls offloading behaviour
• OMP_TEAMS_THREAD_LIMIT – Set the maximum number of threads imposed by teams
• 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
• GOMP_RTEMS_THREAD_POOLS – Set the RTEMS specific thread pools