Little surprised there's no thread or main site article on it, since it's being pimped at places like ARS technica... wondering what other developers think of it.
My own take is that this is attempts to waste time throwing good code after bad. It's being touted as a faster PHP engine that runs in a VM, when the question becomes faster than what? Certainly NOT faster than normal PHP if you read the article.
To help make debugging easier, Facebook's engineers developed their own PHP interpreter, HPHPi, that closely matches how PHP code will behave when converted and compiled.
So they're coders have such convoluted messes they need extra tools to help debug... Ok, that's fine in a development environment; certainly not good for deployment.
Former Facebook software engineer Evan Priestly said in a post on Quora that HPHPi is "roughly twice as slow as PHP."
Ok, that's REALLY not good for deployment... so this new engine, how well does it perform?
according to Facebook software engineer Jason Evans—the performance of the HHVM interpreter is already 60 percent faster than that of the HPHPi interpreter
Now, I'm no mathematical genius, but 1/2*1.6=0.8... meaning this new 'faster' engine is 80% the speed of the normal PHP one... This is an improvement?
Most importantly, it's suited for THEIR development environment and debugging methods, meaning it's pretty much useless outside that; but people keep talking about it on sites like Slashdot and OSNews like it's faster than the regular PHP engine and is meant to be used in production environments -- when it's obviously neither...
Of course, if facebook was REALLY concerned about speed and debugging, they'd just cut the blasted code down and trim out the ridiculous page-bloat... as evidenced by the 50k of code to every k of content delivered client-side; making me dread to think the train wreck they have going on server-side. That pretty much makes me think this entire subject is them blaming the tools instead of the developers.
Really they want speed optimizations and lowered hosting overhead, they should look at the code they are running LONG before dicking around making their own PHP bytecode interpreter. (I'm pretty much refusing to call them VM's anymore -- same for Java. Let's cut the BS and call them what they are)