The environment variables which beginning with OMP_ are defined by
section 4 of the OpenMP specification in version 4.5 or in a later version
of the specification, while those beginning with GOMP_ are GNU extensions.
Most OMP_ environment variables have an associated internal control
variable (ICV).
For any OpenMP environment variable that sets an ICV and is neither
OMP_DEFAULT_DEVICE nor has global ICV scope, associated
device-specific environment variables exist. For them, the environment
variable without suffix affects the host. The suffix _DEV_ followed
by a non-negative device number less that the number of available devices sets
the ICV for the corresponding device. The suffix _DEV sets the ICV
of all non-host devices for which a device-specific corresponding environment
variable has not been set while the _ALL suffix sets the ICV of all
host and non-host devices for which a more specific corresponding environment
variable is not set.
OMP_ALLOCATOR – Set the default allocatorOMP_AFFINITY_FORMAT – Set the format string used for affinity displayOMP_CANCELLATION – Set whether cancellation is activatedOMP_DISPLAY_AFFINITY – Display thread affinity informationOMP_DISPLAY_ENV – Show OpenMP version and environment variablesOMP_DEFAULT_DEVICE – Set the device used in target regionsOMP_DYNAMIC – Dynamic adjustment of threadsOMP_MAX_ACTIVE_LEVELS – Set the maximum number of nested parallel regionsOMP_MAX_TASK_PRIORITY – Set the maximum priorityOMP_NESTED – Nested parallel regionsOMP_NUM_TEAMS – Specifies the number of teams to use by teams regionOMP_NUM_THREADS – Specifies the number of threads to useOMP_PROC_BIND – Whether threads may be moved between CPUsOMP_PLACES – Specifies on which CPUs the threads should be placedOMP_STACKSIZE – Set default thread stack sizeOMP_SCHEDULE – How threads are scheduledOMP_TARGET_OFFLOAD – Controls offloading behaviorOMP_TEAMS_THREAD_LIMIT – Set the maximum number of threads imposed by teamsOMP_THREAD_LIMIT – Set the maximum number of threadsOMP_WAIT_POLICY – How waiting threads are handledGOMP_CPU_AFFINITY – Bind threads to specific CPUsGOMP_DEBUG – Enable debugging outputGOMP_STACKSIZE – Set default thread stack sizeGOMP_SPINCOUNT – Set the busy-wait spin countGOMP_RTEMS_THREAD_POOLS – Set the RTEMS specific thread pools