PHP under the hood

A talk with some examples how PHP works internally. There are also some examples how namespaces and traits are compiled and how to profile a PHP app.

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Transcript

1. PHP under the hood Frank Neff
2. PHP
3. is
4. compiled
5. at
6. runtime!
7. Source code you write...
8. …OpCodes you run
9. Kidding me?
10. Looks confusing, but this is... • how PHP works • cool for debugging purposes • visualizing code complexity • helpful trying to understand opcaches like APC
11. Try it with your code http://explain.php.net.so
12. So this is about profiling?
13. No! XHProf is about profiling • XHProf is a function-level hierarchical profiler for PHP • Reports timing information for every function called • C-Extension can be loaded via PECL • GUI and libs available
14. Looks like this
15. Try it with your code http://xhprof.io/
17. Compiling at runtime is slow!
18. OpCode Cache • Performance enhancing extension for PHP • Hooking into the execution life-cycle • Caching the results of the compilation phase for later reuse • APC • XCache
19. HHVM • HipHop Virtual Machine • Designed for executing PHP programs • Predecessor HPHPc makes C out of PHP • Uses a just-in-time (JIT) compilation • http://www.hhvm.com/
21. \Lets\Talk\About\Namespaces
23. Kidding me?
24. No! • Namespaces in PHP are just class-prefixes • They are added to each classname by the compiler • The result is called a FQCN - Fully Qualified Class Name
28. What do you think of copy & paste code?
30. What do you think of traits?
32. Cool. Traits are for... • Code reusage • Multiple inheritance • Keeping stuff you often use in different contexts • No need for complex OOP architectures
33. Nooooooo!
34. Seriously...
35. No.
36. No. Because traits are... • Copied into every single class at compile- time • Therefore not runtime bindable • Not testable • Tightly coupled • Make it easier to cross SRP (one god-class)
37. (traits === copy & paste)
38. Wanna read more? • PHP at the Core: A Hacker's Guide • PHP Compiler Internals • PHP OpCodes • PHP Internals • Are Traits The New Eval? • PHP-RFC’s
39. So you’re telling me not to use such cool features in PHP?
40. No. Just be aware of how things work in PHP while writing code
42. Frank Neff Software Engineer Thanks http://stickerish.com/ http://xhprof.io/ http://www.vbulletin.com/ http://en.wikipedia.org/ http://blog.supermedia.com/ http://twitter.com/ http://tossfair.wordpress.com/ http://juliannb4.deviantart.com/ http://www.walldime.com/ http://gist.github.com http://meanduchicago.wordpress.com/ Images • @frank_neff • github.com/frne • speakerdeck.com/frne • frankneff.ch • ymc.ch