This variable helps determine how frequently threads switch control. When a
thread executes SWITCH_PERIOD number of selected operations, the threads switch control. The
selected operations are generally comparisons. Comparison operations are used to
cause compute-bound threads to switch.
Setting the value of SWITCH_PERIOD lower increases the overhead spent switching threads, but increases the
uniformity of thread execution. Setting the value very low can significantly
hurt performance. The default value is 500.