HipHop compiles the script to a native language, so I'm actually surprised it only gets a 2x speed gain.
Compiled C++ can usually run many times faster than interpreted PHP, but a converter will never be as efficient as hand crafted code.
Then again, it comes at some costs I believe, such as not supporting the eval statement (so MyBB won't work, although if that's its only shortcoming, it may be patchable).
I would expect an opcode cacher like Xcache to provide most of the benefits of a static compiler like this without that much of a cost.
(10-08-2010 03:39 PM)Firefox Wins Wrote: It isn't multi-threaded, which means it relies on multiple processes to dispatch requests – which means a lot more memory and process juggling than you'd ideally have...
~same source
Only really beneficial if you're running a single process multi-threaded webserver.
I'm not sure how this interfaces, but I believe CGI and FastCGI interfaces require a process per request. So having a multi-threaded endpoint handler isn't that beneficial for any serious webserver (besides, this is static compilation, so mostly irrelevant anyway).