and on OS X you have DTrace (from Solaris), which can be called using dtruss, which is a shell script wrapper around DTrace also, in developer > applications t

and on OS X you have DTrace (from Solaris), which can be called using dtruss, which is a shell script wrapper around DTrace also, in developer > applications there is an app called 'Instruments' which is an excellent GUI front-end to DTrace