Intel® C++ Compiler 16.0 User and Reference Guide
int __cilkrts_get_total_workers (void);
In order to allow more than one user-created thread to share the same set of workers, the runtime system may allocate more worker slots than are active at a given time. The function __cilkrts_get_total_workers returns the total number of worker slots, including those that are not actively in use. If called in serialized code, __cilkrts_get_total_workers returns 1.