Could it be that your Perl implementation simply sucked?

Of course it's possible, though I don't think I'm that bad a coder, and on this project I tried really hard to program using best practices. More likely, IMO, is that the Java implementation had the benefit of months, if not years, of refinement, including optimization.

What in Perl was making it unusable?

The major culprit, by far, was dynamic method resolution. (The implementation was highly OO.)

Simply saying Perl is slow sounds to me like "I didn't really try that hard".

I won't argue with that assertion, but I will point out that I didn't "simply say Perl is slow".

There's no doubt I could have found places for optimization. But the only thing that would have made a major difference was to kill the OO, and that was a sacrifice I wasn't willing to make.

I'm sorry, I don't have actual measurements to give you.