|      Property  |          Description  |    
|     Parameter   type  |        Integer  |   
|     Default   value  |        0  |   
|     Modifiable  |        ALTER SYSTEM  |   
|     Range   of values  |        0 to operating system-specific  |   
|     Basic  |        No  |   
Note:
1.       The RESOURCE_MANAGER_CPU_ALLOCATION parameter is deprecated. It is retained for backward compatibility only.
2.       RESOURCE_MANAGER_CPU_ALLOCATION specifies the number of CPUs that the Resource Manager should utilize. The Resource Manager controls how a system's CPUs are utilized by its database's sessions.
The Resource Manager schedules database sessions on the CPUs according to a Resource Plan that has been configured and enabled by the DBA. Normally, the Resource Manager schedules enough database sessions to keep all CPUs utilized. However, in some scenarios, a DBA may only want to schedule enough database sessions to keep a subset of the CPUs utilized.
3.       Query for the current value of the parameter
select name, value, isdefault, isses_modifiable, issys_modifiable, 
       isinstance_modifiable, isdeprecated, description 
from   v$parameter 
where upper(name) = 'RESOURCE_MANAGER_CPU_ALLOCATION';
Oracle initializatoin parameters