OPcache Preloading
OPcache preloading, introduced in version 7.4, allows loading PHP files into shared memory at PHP-FPM startup so they are permanently available to all worker processes without any parsing overhead on each request.
A preload script is specified with opcache.preload in php.ini. All files required or compiled in that script are cached for the lifetime of the PHP-FPM master process. Changes to preloaded files require a PHP-FPM restart to take effect.
Preloading is most effective for framework core files, base classes, and heavily-used libraries.
<?php
// preload.php, as referenced in php.ini:
// opcache.preload = /var/www/preload.php
// opcache.preload_user = www-data
// Preload all PHP files from the framework kernel
$dir = new RecursiveDirectoryIterator('/var/www/vendor/symfony/http-kernel');
$iter = new RecursiveIteratorIterator($dir);
foreach ($iter as $file) {
if ($file->getExtension() === 'php') {
opcache_compile_file($file->getPathname());
}
}
?>