Yesterday's tests show that using gcc on both FreeBSD and Solaris yields a marked improvement in the time taken to compile Perl.
However, despite the big difference in compile times, the run-times of Perl's test suite aren't dramatically affected. The worst performer, Perl running on Solaris, compiled with Sun's cc and optimisation is 6% slower than the best performer, Perl running on FreeBSD, compiled with gcc and optimisation. This test involved a great deal of IO and process creation, and I thought that that might be part of the reason for the differences. So I've been using a Perl based application, SpamAssassin, to test whether or not there are big differences between the run times of the various Perl interpreters.