A lot of interesting work has been going into the HipHop Virtual Machine since its 2.1 release earlier in the summer. According to its Git NEWS page, the next release is planned for next month (possibly the 2nd of September) and there's been lots of changes procuring:
- Implementatations of stream_is_local, asserts with string arguments, PHAR read support, RecursiveArrayIterator, php_strip_whitespace(), and get_included_files().
- Limited use of huge pages.
- Timeouts in the CLI mode.
- A Redis session handler.
- A new hhprof memory profiler that is compatible with the pprof output.
- HHBC is enabled by default in debug builds.
- An initial implementation of xhpast2 to replace xhpast.
- Mac OS X compilation support.
- Better JIT code generation.
- Redix extension support.
- PHP 5.4's SessionHandler is now supported.
Look for this high-performance PHP implementation to be out in September.