We had such floating point printing performance issues in java once that i needed to implement a grisu variant that didn't fall into bignum calculations and had few other tweaks to short circuit the printing and improve some common cases. It made a decent impact especially on garbage generation (it was specifically zero gc). Since been ported to a couple other languages, and I was thinking of redoing it lately for another project and using the newer algo. https://github.com/jnordwick/zerog-grisu
