Problem with perf data


I have installed nagios, ndoutils and all went fine
to generate values in the form of graphs i need perfdata values

But in my nagios database the nagios status table and all other tables which contain perfdata is having NULL(empty space) as the value.

I have checked it by giving

process_performance_data=0 and 1 as well

but found no result.

how to get values in this perfdata

Any help appreciated,