What I get from skimming this article, it's just obsessing around premature optimization and small techniques to shave off "hundreds of microseconds or even whole seconds" from the runtime of programs. It doesn't mention Benchmark.pm, it does mention the profiler only in passing, and it doesn't mention the fact that optimizing/changing your algorithm to a better suited algorithm will most likely give a much bigger gain than any string concatenation optimization. The author mentions "compiling to C" via the perlcc backend as a viable option without telling the limits of this process and what the magic "compile your Perl to C" bullet actually will accomplish.

The one article about hardcore optimization of Perl code is When Perl is not quite fast enough by Nicholas Clark, and the IBM article doesn't go that way.

I am not really fond of these drive-by article spammings by the IBM Developerworks, and I'd prefer if IBM Developerworks offered a subscriber method so that the folks interested in the articles can be notified without "Perl News" also being spammed by this.

Update: On second reading, the author mentions what perlcc does. I still wonder what the sense is, at it only reduces startup time, which is negligible for long-running processes.
Added link to Nicholas Clarks "When Perl is not quite fast enough" talk