PHP accelerator

A PHP accelerator is a PHP extension designed to improve the performance of software applications written in the PHP programming language.

Operation

Most PHP accelerators work by caching the compiled bytecode of PHP scripts to avoid the overhead of parsing and compiling source code on each request (some or all of which may never even be executed). To further improve performance, the cached code is stored in shared memory and directly executed from there, minimizing the amount of slow disk reads and memory copying at runtime.

Practical benefits

A PHP accelerator typically reduces server load and increases the speed of PHP code by a factor of anywhere between 2–10 times, depending on factors such as the inherent execution time of the PHP application and the percentage of source code actually executed on a given request. While a code optimizer may even slow down overall performance when used in isolation, it can provide an additional performance boost when coupled with a bytecode cache; as the optimization effort is performed just once.

See also

• List of PHP accelerators

External links

• Benchmarking Drupal with PHP op-code caches: APC, eAccelerator and XCache (and Standard PHP) compared from April 2008.
• PHP on Fire: Five Opcode Caches compared including a complete chart featuring Zend Platform, APC, XCache, eAccelerator ionCube Encoder and Standard PHP benchmarks. Made in October 2006.
• Alternative PHP Cache available as a PHP extension.