Compare functions in two versions of a CPAN distro

Does there exist already a program to compare the performance of a 
function between two different versions of the CPAN distribution?

I have uploaded List-Compare-0.40 to CPAN.  The changes from 0.39 should 
improve the performance of several functions.  The actual code changes 
are deep inside helper functions.  I have benchmarked the differences 
between the 0.39 and 0.40 versions of those helper functions by 
extracting them into a separate Perl program using Benchmark.  But I 
would like to be able to measure and display the difference at the API 
level.

I suspect that with effort I could write such a program, but it sounds 
like the sort of thing that someone on cpan.workers would already have 
written.

Suggestions?

Thank you very much.
Jim Keenan