Talk about the goto() overhead in the documentation

diff --git a/lib/Scope/Upper.pm b/lib/Scope/Upper.pm
index c40f1c8d48cf0515eb7c529bdc0b658250bed8c9..eefe25362df85b9fdabf14a419e3351f9917434a 100644 (file)
--- a/lib/Scope/Upper.pm
+++ b/lib/Scope/Upper.pm
@@ -523,6 +523,9 @@ It may help to use a perl higher than 5.8.9 or 5.10.0, as they contain some cont
 Calling C<goto> to replace an L</uplevel>'d code frame does not work when a custom runloop is used or when debugging flags are set with C<perl -D>.
 In those two cases, L</uplevel> will look for a C<goto &sub> statement in its callback and, if there is one, throw an exception before executing the code.
 
+Moreover, in order to handle C<goto> statements properly, L</uplevel> currently has to suffer a run-time overhead proportional to the size of the the callback in every case (with a small ratio), and proportional to the size of B<all> the code executed as the result of the L</uplevel> call (including subroutine calls inside the callback) when a C<goto> statement is found in the L</uplevel> callback.
+Despite this shortcoming, this XS version of L</uplevel> should still run way faster than the pure-Perl version from L<Sub::Uplevel>.
+
 =head1 DEPENDENCIES
 
 L<XSLoader> (standard since perl 5.006).