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.

nytprof stands for 'new york times profiler'. indeed, this module was initially developed from devel::fastprof by the new york times co. to help their developers quickly identify bottlenecks in large perl applications.