A week ago, I let ya'll know that the core PHP team had been brought to Facebook's main campus. That team were forced to sign NDA's, and taken to a very quiet, secluded meeting room where some cool new Facebook-backed open source project was described.
Well, I was able to put all the pieces together on this one, finally, and I now understand exactly what is up: Facebook has rewritten the PHP runtime from scratch. This coming Tuesday, they will make a big announcement around this project, and will make it available as open source software. I'm not really sure of any of the details of the project, but I do know that Facebook hired someone two years ago to do this, and I'm relatively sure this was a one-man project during that entire time.
So, why has Facebook rewritten the PHP runtime? Because PHP is obviously too slow for their tastes. A few years ago, I had a coffee meeting with some of the folks from Zend. When they asked what I had been hearing about PHP in the market from my sources, I hemmed and hawed, then told them that I had heard people complaining about how slow PHP was. Now, I don't personally consider PHP slow: it is simply not a language designed for the sorts of workloads that Java and .NET are.
But that still doesn't change the fact that PHP can be a tad pokey on the server. Well, when I said this to the Zend folks, their immediate reaction was similar to that of a gestapo officer looking for a spy: "What? Who said that? Tell us their name!"
Clearly, Zend does not think there is a problem. But Facebook did. Not enough of a problem to support more than one paycheck, but then, considering how many users they have, even a 1 percent performance gain would be a massive help.
This Tuesday, salvation should arrive. I would imagine this new project will push a lot of the weight in the PHP community into Facebook's corner of the world. It will be nice to see what they can do with all that interest, since Yahoo!, in the same position 6 years ago, largely squandered their opportunity to mold PHP into a more robust platform and language.
UPDATE: After sifting through the comments here and elsewhere, I'm inclined to agree with the folks who are saying that Facebook will be introducing some sort of compiler for PHP. This sounds highly plausible, and fits into what I've heard. Obviously, I don't have absolute specifics. Thanks for the extra info, readers.