Using the affinity Option

On multiprocessor computers that support processor affinity, the affinity option specifies the CPUs to which the database server binds virtual processors.

The affinity option has the following two forms:

aff=processor_number
aff=start_range,end_range

In the first form, the database server binds all virtual processors in the class to the CPU numbered processor_number. (On a multiprocessor system, the operating system numbers the CPUs from 0 to (number of CPUs-1)). In the second form, the database server assigns the virtual processors of the class to processors in the range start_range to end_range, inclusive. The value end_range must be larger than start_range, and all values must be less than the total number of available CPUs.

For example, if your platform has eight CPUs, your ONCONFIG file might include the following VPCLASS entries:

VPCLASS     first,aff=3
VPCLASS     second,num=3,aff=5-7
VPCLASS     cpu,num=8,aff=0-7,noage

For more information about using processor affinity, refer to the chapter on virtual processors in the IBM Informix Administrator's Guide.