On Nov 19, 2010, at 11:10 AM, Benedikt Meurer wrote:
Well, it is a research project, and it was driven by actual demand. A JIT engine for PHP is something less interesting from a university point of view, unless there are companies willing to sponsor/help the development.
But from my personal experience, there is not really a lot to gain w.r.t. PHP. Delivering website content does not involve complex computations or processing, it is mostly I/O bound, depending on a fast database engine, a fast webserver, decent text processing throughput, etc. I may be wrong here,
I think you are. As said by someone previously facebook got a 2x speedup on CPU by optimizing PHP. Websites are not just
getting something from a database and echoing it.
but I doubt that you'd see relevant speedups on large websites by simply JITting the PHP code.
Also PHP code is less likely to change at runtime, so there's no real need to acutally JIT compile it. You could use a lot simpler techniques here to improve performance. For example, just write a simple PHP to C compiler, compiling your PHP code to native code via C, and let the webserver run the native code instead. With some clever compilation scheme, this should outperform any JIT engine, with a lot less effort.
I think it may actually be more effort to do an efficient compiler than a JIT on languages like PHP
For instance the team behind the Druby project (
http://www.cs.umd.edu/projects/PL/druby/publications.html )
first tried to do some static type inference on ruby code but then switched to a dynamic approach
because it was too hard to infer statically.