done in the subroutine peep(). Optimizations performed at this stage
are subject to the same restrictions as in the pass 2.
+=head2 Pluggable runops
+
+The compile tree is executed in a runops function. There are two runops
+functions in F<run.c>. C<Perl_runops_debug> is used with DEBUGGING and
+C<Perl_runops_standard> is used otherwise. For fine control over the
+execution of the compile tree it is possible to provide your own runops
+function.
+
+It's probably best to copy one of the existing runops functions and
+change it to suit your needs. Then, in the BOOT section of your XS
+file, add the line:
+
+ PL_runops = my_runops;
+
+This function should be as efficient as possible to keep your programs
+running as fast as possible.
+
=head1 Examining internal data structures with the C<dump> functions
To aid debugging, the source file F<dump.c> contains a number of