jaredor,

Thanks for your input. If you notice in the original post I said "use bytes" to eliminate concerns about UCA.

perl -e 'use bytes;$s1="abcd";$s2="abcz";$dif=$cmp=$s1 cmp $s2;print "
+$dif\t$cmp\n";'
[download]

The performance hit for using UCA is just too great. In some of my tests, the performance was degradated by as much as 10,000%. As for "bit-wise operations on strings", I have a math background and started programming by writing code in machine language, and later assembler, Basic, Fortran, C, and a lot of others, until I had the good fortune of being introduced to Perl.

To explain why performance is so critical, I have been writing a "pure-perl" data base engine, to replace Oracle's BerkeleyDB and MySQL in all of our products. So our goal was to come within 20% of the performance of Oracle products. As it turns out, our clients will see enhanced performance when we switch them over, and we will be able to provide database support on any platform that Perl runs on. (An area where Perl excels!)

I have been very impressed with the performance of Perl since 5.8.x. So in profiling( -d:NTYProf ) of the code, the routine I asked about, is called 14,595,348 times on a test of writing 100K records. So even a slight improvement would be welcome. Thanks to the PM answers, I got a 376% increase in performance. Great!
(Note: Some of our clients have databases with billions of records.)

When I wrote Perl performance just gets better and better! my intent was in showing that Perl has improved over the years. It was the first time that I had an actual test case to run on several versions of Perl from 5.6.1 to 5.12.2. Since then I have tested with 5.14.2 with even better results. I don't know why Perl performance is improving for this type of work, but I can demonstrate that it is. I also have incorrectly used the term "modern Perl" in the past, since I didn't realize that a module "Modern::Perl" existed.

Thank you and Good Luck!