php under the_hood
TRANSCRIPT
PHP under the hoodFrank Neff
PHP
is
compiled
at
runtime!
Source code you write...
…OpCodes you run
Kidding me?
Looks confusing, but this is...
● how PHP works● cool for debugging purposes● visualizing code complexity● helpful trying to understand opcaches like
APC
Try it with your code
http://explain.php.net.so
So this is about profiling?
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
Looks like this
Try it with your code
http://xhprof.io/
Compiling at runtime is slow!
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
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/
\Lets\Talk\About\Namespaces
Kidding me?
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
What do you think of copy & paste code?
What do you think of traits?
Cool. Traits are for...
● Code reusage● Multiple inheritance● Keeping stuff you often use in different
contexts● No need for complex OOP architectures
Nooooooo!
Seriously...
No.
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)
(traits === copy & paste)
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
So you’re telling me not to use such cool features in PHP?
No.
Just be aware of how things work in PHP while writing code
Frank NeffSoftware Engineer
Thankshttp://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.comhttp://meanduchicago.wordpress.com/
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