I've posted a chronological account of my day at blogs.perl.org. Here is the condensed version.
I learned parallel programming, and programming on nVidia video cards, back in 2010. By early 2011, I had written a few modules to make it easer to write CUDA, using Perl mostly for the memory shuffling. Today, I brushed off the first (ExtUtils::nvcc) and I realized that the second---CUDA::Minimal---works on all versions of Perl except v5.16.
A few months ago I concluded that CUDA::Minimal was doomed when it didn't compile on v5.16. Now that I know that it compiles on v5.18, I'm a lot happier!