PHP Manual: Installation

Installation

OPcache can only be compiled as a shared extension. If you have disabled the building of default extensions with --disable-all, you must compile PHP with the --enable-opcache option for OPcache to be available.

Once compiled, you can use the zend_extension configuration directive to load the OPcache extension into PHP. This can be done with zend_extension=/full/path/to/opcache.so on non-Windows platforms, and zend_extension=C:\path\to\php_opcache.dll on Windows.

Note:
If you want to use OPcache with » Xdebug, you must load OPcache before Xdebug.

Recommended php.ini settings

The following settings are generally recommended as providing good performance:

opcache.memory_consumption=128
opcache.interned_strings_buffer=8
opcache.max_accelerated_files=4000
opcache.revalidate_freq=60
opcache.fast_shutdown=1 ; prior to PHP 7.2.0
opcache.enable_cli=1

You may also want to consider disabling opcache.save_comments and enabling opcache.enable_file_override, however note that you will have to test your code before using these in production as they are known to break some frameworks and applications, particularly in cases where documentation comment annotations are used.

On Windows, opcache.file_cache_fallback should be enabled, and opcache.file_cache should be set to an already existing and writable directory.

A full list of configuration directives supported by OPcache is also available.