Facebook releases HHVM, 60 percent faster than its current PHP interpreter
I find it interesting that the economics of inertia work out in favor of Facebook expending so much effort in improving the performance of a historically technologically poor language like PHP.Jason Evans is the author of jemalloc (and more). Given all the things he would be capable of applying himself to, it's surprising to see him working on PHP runtime performance (though, the problems are interesting).