On DZone.com today there's a post covering the different kinds of handlers that can execute PHP - those pieces of code that work with the web servers we use every day to interpret and execute PHP code.

PHP Handlers? mod_php? FPM? How do we make sense of the inner workings of PHP outside of our lines of code? We know we can run PHP on the server to build web applications swiftly, but how can we optimize our environment and configurations to reach maximum scale? We know that PHP has its drawbacks for not being asynchronous or event-driven, which is all the more reason to ensure maximum optimization. The impact of your server environment on your PHP application performance can be more than you think you can afford. A careful examination of your PHP ecosystem will help you avoid suffering performance loss in areas you can otherwise solve for easily.

They provide a brief summary of what PHP handers, well, handle and where they fit in the overall architecture of execution. They then get into the details on some of them:

• CGI – mod_cgi
• suPHP – mod_suphp
• DSO – mod_php
• FastCGI – mod_fcgid
• FPM (FastCGI Process Manager) – php-fpm

Included in each is an overview of how it works and some of the main advantages (and disadvantages) of their use. He also mentions two of the most popular web servers that work with these handlers: Apache and Nginx.

In this new post to his site Kevin Schroeder takes a look at the performance difference between Apache+mod_php and Nginx+FastCGI and why the second is noticeably faster than the second.

I was originally going to write a blog post about why NginX with FastCGI was faster than Apache with mod_php. I had heard a while ago that NginX running PHP via FastCGI was faster than Apache with mod_php and have heard people swear up and down that it was true. I did a quick test on it a while back and found some corresponding evidence. Today I wanted to examine it more in depth and see if I could get some good numbers on why this was the case. The problem was that I couldn’t.

He uses a "hello world" script as a baseline to do some testing and the ab to run the numbers. His results show a pretty significant difference between the two setups and an "strace" on Apache showed a clear "winner" as to why it's slower (reading the .htaccess file). Once he turned this off, though, Apache jumped up and started performing better than Nginx.

This all makes sense. mod_php has PHP embedded in Apache and so it should be faster. If you're running only PHP on a web server then Apache still seems to be your best bet for performance. And if you are seeing a significant performance difference then you should check if AllowOverride is turned on. If it is, try moving that into httpd.conf and try again.

On his blog today Matthew Weier O'Phinney talks about how to run mod_php and FastCGI side-by-side on a Zend Server instance.

I installed Zend Server some time ago, so I'm still on a PHP 5.2 mod_php binary. I have several PHP 5.3 binaries compiled and installed locally for running unit tests and sample scripts already -- so the question was how to keep my 5.2 mod_php running while simultaneously allowing the ability to run selected vhosts in 5.3? The answer can be summed up in one acronym: FastCGI.

He shows how to enable FastCGI in Apache (on Ubuntu), make a virtual host for your site and create a "cgi-bin" directory to contain the script(s) for your PHP versions as CGIs.