If that is all you took from my post, then you shouldn't be celebrating.

If all the programs you write do nothing more complicated than wc or fgrep; if in your world a 1GB file represents nothing more important than say 1 day's twaterrings, and you only need to count the number of '!'s used; if between reading and writing your important data you need to do nothing of any consequence; then stick with your un-threaded perl, because it can do nothing very, very quickly.

On the other hand, if you are (say) a bio-geneticist. And that 1GB of data represents 10,000 x 100k base sequences, each of which need to be fuzzy matched at every offset, against each of 25,000 x 25-base sub-sequences; a process that on a single core takes a week or more, then you'll be rather more interested in using perl's threading to reduce that to under a day using a commodity 8-core box. And even more grateful for that threading when you're given access to the departmental 128-core processor, and your script completes in under 2 hours with nothing more than a change of command line argument.