I normally use following two :

1. HP caliper : its very good tool for monitoring processes it you can check call graph and other low level information also. But please note its free only for personal use

2. daemontools : daemontools is a collection of tools for managing UNIX service

I normally use following two :

1. HP caliper : its very good tool for monitoring processes it you can check call graph and other low level information also. But please note its free only for personal use.

2. daemontools : a collection of tools for managing UNIX services