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Oracle® Developer Studio 12.6: OpenMP API User's Guide

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Updated: June 2017
 
 

9.2 OpenMP Internal Control Variables

The following internal control variables are defined by the implementation:

  • bind-var: Controls the binding of threads to places. The initial value of bind-var is FALSE.

  • default-device-var: Controls the default target device. The initial value of default-device-var is 0 (the host device).

  • def-sched-var: Controls the implementation defined default scheduling of loop regions. The initial value of def-sched-var is static with no chunk size.

  • dyn-var: Controls whether dynamic adjustment of the number of threads is enabled for encountered parallel regions. The initial value of dyn-var is TRUE (that is, dynamic adjustment is enabled).

  • max-active-levels-var: Controls the maximum number of nested active parallel regions. The initial value of max-active-levels-var is 4.

  • nthreads-var: Controls the number of threads requested for encountered parallel regions. The initial value of nthreads-var is equal to the number of cores, capped at 32.

  • place-partition-var: Controls the place partition available to the execution environment for encountered parallel regions. The initial value of place-partition-var is cores.

  • run-sched-var: Controls the schedule that the schedule(runtime) clause uses for loop regions. The initial value of run-sched-var is static with no chunk size.

  • stacksize-var: Controls the stack size for threads that the OpenMP implementation creates (also known as helper threads). The initial value of stacksize-var is 4 Megabytes for 32-bit applications, and 8 Megabytes for 64-bit applications.

  • thread-limit-var: Controls the maximum number of threads participating in the OpenMP program. The initial value of thread-limit-var is 1024.

  • wait-policy-var: Controls the desired behavior of waiting threads. The initial value of wait-policy-var is PASSIVE.