system tap profiling

[Ivan Novick <novickivan at gmail dot com>]

Hello,

I am comparing a number of tools for performance profiling including
system tap, oprofile, and gperf.

Both oprofile and gperf can determine how much time is spent in the
functions of a running program, however, they are fooled when a
process is waiting on IO because the process will not be running in
the CPU when the tool samples the current state of the process.

What I have seen from systemtap, it can profile user function calls
from entry and exit and record a timestamp.  Essentially it can
measure wall clock time for all user functions in an application,
regardless of whether they are in CPU or doing IO.

Am I correct on this, or would there be some reason that system tap
can not produce a report showing all user functions and the amount of
wall clock time spent in each function?

Cheers,
Ivan Novick