Devel::NYTProf is a powerful feature-rich perl source code profiler.

* Performs per-line statement profiling for fine detail
* Performs per-subroutine statement profiling for overview
* Performs per-block statement profiling (the first profiler to do so)
* Accounts correctly for time spent after calls return
* Performs inclusive and exclusive timing of subroutines
* Subroutine times are per calling location (a powerful feature)
* Can profile compile-time activity, just run-time, or just END time
* Uses novel techniques for efficient profiling
* Sub-microsecond (100ns) resolution on systems with clock_gettime()
* Very fast - the fastest statement and subroutine profilers for perl
* Handles applications that fork, with no performance cost
* Immune from noise caused by profiling overheads and I/O
* Program being profiled can stop/start the profiler
* Generates richly annotated and cross-linked html reports
* Trivial to use with mod_perl - add one line to httpd.conf
* Includes an extensive test suite
* Tested on very large codebases

NYTProf is effectively two profilers in one: a statement profiler, and a
subroutine profiler.