While trying to find the amount of physical memory used by oracle process on AIX, I got reference of a document from Metalink:
It tell us about which process is using how much memory and how to interpret the output of commands like: vmstat, svmon, ps on AIX.
Also, to get more information on AIX parameter like: MAXPERM, MINPERM click here
Though I have not explored the complete guide yet, but found it very good to start with.