i found it pretty inspiring. not only was it a neat example of coding with instruction-level parallelism in mind, but a concrete demonstration that it did indeed provide significant speedups in a piece of code that people have been using for decades (and which had presumably already been optimised for the single-everything cpu case)
The dynamic class is a cool idea, i'm glad it's faster for their use case, and it's nice to have canonical implementations of format and json_parse. Aside from that, seems pretty unnoteworthy - Does this fit into HipHop, or do Facebook have another large C++ project?
Why are so many conversions needed? "they have many protocols that store ints as strings" why?