PHP on Windows Optimized build—Thread Safe version too!

I’ve just finished tweakin’ out the PGO (Profiled Guided Optimization) build script for PHP on Windows to crank out the thread-safe version of PHP as well.

So, now you can test PHP 5.3 RC3-dev PGO optimized for Windows with Apache 2.2!

What’s the difference between thread-safe and non-thread-safe?

The non-thread-safe version of PHP should be used when there is a single request per instance of PHP–like, when you use FastCGI—a single PHP-CGI.EXE handles a single request at a time, and the Web Server spins off multiple instances of PHP-CGI.EXE to handle requests in parallel. Because each instance is in a separate process, there is no need to have all the thread-safety code in PHP.

The thread-safe version is required when you use PHP as a module—as you would in Apache on Windows—and the WebServer handles multiple requests in the same process.

Given the choice, the non-thread-safe version should be faster, and if you can, you should probably use that one.

You can read more about this at

If you already use the thread-safe version of PHP on Windows, please download and test this version if you can—and send me some feedback! 

Links to the latest PHP 5.3 Builds:

PHP 5.3-RC-dev snapshots:


Thread Safe: