Opcache 能够将代码编译成字节码，能够加快脚本的运行。
检查是否安装 opcache：
php -v
PHP 7.3.22 (cli) (built: Sep 3 2020 21:16:44) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.22, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.3.22, Copyright (c) 1999-2018, by Zend Technologies
如果有 OPcache 即已经安装。
配置项：
; Enable Zend OPcache extension module
zend_extension=opcache
; Determines if Zend OPCache is enabled
opcache.enable=1
; Determines if Zend OPCache is enabled for the CLI version of PHP
;opcache.enable_cli=0
; The OPcache shared memory storage size.
opcache.memory_consumption=128
; The amount of memory for interned strings in Mbytes.
opcache.interned_strings_buffer=8
; The maximum number of keys (scripts) in the OPcache hash table.
; Only numbers between 200 and 1000000 are allowed.
opcache.max_accelerated_files=4000
; The maximum percentage of "wasted" memory until a restart is scheduled.
;opcache.max_wasted_percentage=5
; When this directive is enabled, the OPcache appends the current working
; directory to the script key, thus eliminating possible collisions between
; files with the same name (basename). Disabling the directive improves
; performance, but may break existing applications.
;opcache.use_cwd=1
; When disabled, you must reset the OPcache manually or restart the
; webserver for changes to the filesystem to take effect.
;opcache.validate_timestamps=1
; How often (in seconds) to check file timestamps for changes to the shared
; memory storage allocation. ("1" means validate once per second, but only
; once per request. "0" means always validate)
;opcache.revalidate_freq=2
; Enables or disables file search in include_path optimization
;opcache.revalidate_path=0
; If disabled, all PHPDoc comments are dropped from the code to reduce the
; size of the optimized code.
;opcache.save_comments=1
; Allow file existence override (file_exists, etc.) performance feature.
;opcache.enable_file_override=0
; A bitmask, where each bit enables or disables the appropriate OPcache
; passes
;opcache.optimization_level=0x7FFEBFFF
; This hack should only be enabled to work around "Cannot redeclare class"
; errors.
;opcache.dups_fix=0
; The location of the OPcache blacklist file (wildcards allowed).
; Each OPcache blacklist file is a text file that holds the names of files
; that should not be accelerated.
opcache.blacklist_filename=/etc/php.d/opcache*.blacklist
; Allows exclusion of large files from being cached. By default all files
; are cached.
;opcache.max_file_size=0
; Check the cache checksum each N requests.
; The default value of "0" means that the checks are disabled.
;opcache.consistency_checks=0
; How long to wait (in seconds) for a scheduled restart to begin if the cache
; is not being accessed.
;opcache.force_restart_timeout=180
; OPcache error_log file name. Empty string assumes "stderr".
;opcache.error_log=
; All OPcache errors go to the Web server log.
; By default, only fatal errors (level 0) or errors (level 1) are logged.
; You can also enable warnings (level 2), info messages (level 3) or
; debug messages (level 4).
;opcache.log_verbosity_level=1
; Preferred Shared Memory back-end. Leave empty and let the system decide.
;opcache.preferred_memory_model=
; Protect the shared memory from unexpected writing during script execution.
; Useful for internal debugging only.
;opcache.protect_memory=0
; Allows calling OPcache API functions only from PHP scripts which path is
; started from specified string. The default "" means no restriction
;opcache.restrict_api=
; Enables and sets the second level cache directory.
; It should improve performance when SHM memory is full, at server restart or
; SHM reset. The default "" disables file based caching.
; RPM note : file cache directory must be owned by process owner
; for mod_php, see /etc/httpd/conf.d/php.conf
; for php-fpm, see /etc/php-fpm.d/*conf
;opcache.file_cache=
; Enables or disables opcode caching in shared memory.
;opcache.file_cache_only=0
; Enables or disables checksum validation when script loaded from file cache.
;opcache.file_cache_consistency_checks=1
; Implies opcache.file_cache_only=1 for a certain process that failed to
; reattach to the shared memory (for Windows only). Explicitly enabled file
; cache is required.
;opcache.file_cache_fallback=1
; Validate cached file permissions.
; Leads OPcache to check file readability on each access to cached file.
; This directive should be enabled in shared hosting environment, when few
; users (PHP-FPM pools) reuse the common OPcache shared memory.
;opcache.validate_permission=0
; Prevent name collisions in chroot'ed environment.
; This directive prevents file name collisions in different "chroot"
; environments. It should be enabled for sites that may serve requests in
; different "chroot" environments.
;opcache.validate_root=0
; If specified, it produces opcode dumps for debugging different stages of
; optimizations.
;opcache.opt_debug_level=0
; Enables or disables copying of PHP code (text segment) into HUGE PAGES.
; This should improve performance, but requires appropriate OS configuration.
opcache.huge_code_pages=0
/
注：当部署新版本时，需要清空 opcache 的缓存，需要重启 php-fpm 。