The GET_CPU_COUNT function is used to determine the maximum number of processors to use when executing an operation in parallel. The resulting count is used to set the degree of parallelism for a session when the SET_PARALLEL procedure is executed and 0 (maximum) is specified.
The resulting CPU_COUNT is based on the CPU_COUNT from V$PARAMETER minus 1 for less than 8 CPU's or minus 2 for 8 or more CPU's.
Example
SELECT IN_DB_UTIL.GET_CPU_COUNT FROM DUAL;