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221 lines
8.7 KiB
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221 lines
8.7 KiB
Plaintext
The Zend OPcache
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================
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The Zend OPcache provides faster PHP execution through opcode caching and
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optimization. It improves PHP performance by storing precompiled script
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bytecode in the shared memory. This eliminates the stages of reading code from
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the disk and compiling it on future access. In addition, it applies a few
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bytecode optimization patterns that make code execution faster.
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Compatibility
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-------------
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This version of Zend OPcache is compatible with PHP 5.2.*, 5.3.*, 5.4.*
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and PHP-5.5 development branch. PHP 5.2 support may be removed in the future.
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Quick Install
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-------------
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- Compile
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$PHP_DIR/bin/phpize
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./configure \
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--with-php-config=$PHP_DIR/bin/php-config
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make
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- Install
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make install # this will copy opcache.so into PHP extension directory
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- Edit php.ini
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zend_extension=/...full path.../opcache.so
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NOTE: In case you are going to use Zend OPcache together with Xdebug or Zend Debugger,
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be sure that the debugger is loaded after OPcache. "php -v" must show the debugger
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after OPcache.
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- Restart PHP
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Speed Tuning
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-------------
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We recommend the following configuration options for best performance
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in a production environment.
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opcache.memory_consumption=128
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opcache.interned_strings_buffer=8
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opcache.max_accelerated_files=4000
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opcache.revalidate_freq=60
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opcache.fast_shutdown=1
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opcache.enable_cli=1
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You also may add the following, but it may break some applications and
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frameworks. Please, read description of these directives and add them on your
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own risk.
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opcache.save_comments=0
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opcache.enable_file_override=1
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In some cases you may like to prefer enabling/disabling some features
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to avoid incompatibilities at the cost of some performance degradation.
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For development environment we would recommend setting opcache.revalidate_freq
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into 0.
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Configuration Directives
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------------------------
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opcache.enable (default "1")
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OPcache On/Off switch. When set to Off, code is not optimized and cached.
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opcache.enable_cli (default "0")
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Enables the OPcache for the CLI version of PHP. It's mostly for testing
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and debugging.
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opcache.memory_consumption (default "64")
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The OPcache shared memory storage size. The amount of memory for storing
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precompiled PHP code in Mbytes.
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opcache.interned_strings_buffer (default "4")
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The amount of memory for interned strings in Mbytes.
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opcache.max_accelerated_files (default "2000")
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The maximum number of keys (scripts) in the OPcache hash table.
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The number is actually the first one in the following set of prime
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numbers that is bigger than the one supplied: { 223, 463, 983, 1979, 3907,
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7963, 16229, 32531, 65407, 130987, 262237, 524521, 1048793 }. Only numbers
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between 200 and 1000000 are allowed.
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opcache.max_wasted_percentage (default "5")
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The maximum percentage of "wasted" memory until a restart is scheduled.
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opcache.use_cwd (default "1")
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When this directive is enabled, the OPcache appends the current working
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directory to the script key, thus eliminating possible collisions between
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files with the same name (basename). Disabling the directive improves
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performance, but may break existing applications.
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opcache.validate_timestamps (default "1")
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When disabled, you must reset the OPcache manually or restart the
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webserver for changes to the filesystem to take effect.
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The frequency of the check is controlled by the directive
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"opcache.revalidate_freq".
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opcache.revalidate_freq (default "2")
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How often (in seconds) to check file timestamps for changes to the shared
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memory storage allocation. ("1" means validate once per second, but only
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once per request. "0" means always validate)
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opcache.file_update_protection (default "2")
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Prevents caching files that are less than this number of seconds old.
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It protects from caching of incompletely updated files. In case all file
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updates on your site are atomic, you may increase performance setting it
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to "0".
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opcache.revalidate_path (default "0")
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Enables or disables file search in include_path optimization
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If the file search is disabled and a cached file is found that uses
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the same include_path, the file is not searched again. Thus, if a file
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with the same name appears somewhere else in include_path, it
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won't be found. Enable this directive if this optimization has an effect on
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your applications. The default for this directive is disabled, which means
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that optimization is active.
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opcache.save_comments (default "1")
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If disabled, all PHPDoc comments are dropped from the code to reduce the
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size of the optimized code. Disabling "Doc Comments" may break some
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existing applications and frameworks (e.g. Doctrine, ZF2, PHPUnit)
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opcache.load_comments (default "1")
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If disabled, PHPDoc comments are not loaded from SHM, so "Doc Comments"
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may be always stored (save_comments=1), but not loaded by applications
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that don't need them anyway.
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opcache.fast_shutdown (default "0")
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If enabled, a fast shutdown sequence is used for the accelerated code
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The fast shutdown sequence doesn't free each allocated block, but lets
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the Zend Engine Memory Manager do the work.
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opcache.enable_file_override (default "0")
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Allow file existence override (file_exists, etc.) performance feature.
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opcache.optimization_level (default "0xffffffff")
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A bitmask, where each bit enables or disables the appropriate OPcache
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passes
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opcache.inherited_hack (default "1")
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Enable this hack as a workaround for "Cannot redeclare class" errors.
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The OPcache stores the places where DECLARE_CLASS opcodes use
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inheritance (These are the only opcodes that can be executed by PHP,
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but which may not be executed because the parent class is missing due to
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optimization). When the file is loaded, OPcache tries to bind the
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inherited classes by using the current environment. The problem with this
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scenario is that, while the DECLARE_CLASS opcode may not be needed for the
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current script, if the script requires that the opcode at least be defined,
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it may not run. The default for this directive is disabled, which means
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that optimization is active. In php-5.3 and above this hack is not needed
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anymore and this setting has no effect.
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opcache.dups_fix (default "0")
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Enable this hack as a workaround for "Cannot redeclare class" errors.
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opcache.blacklist_filename
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The location of the OPcache blacklist file (wildcards allowed).
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Each OPcache blacklist file is a text file that holds the names of files
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that should not be accelerated. The file format is to add each filename
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to a new line. The filename may be a full path or just a file prefix
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(i.e., /var/www/x blacklists all the files and directories in /var/www
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that start with 'x'). Line starting with a ; are ignored (comments).
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Files are usually triggered by one of the following three reasons:
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1) Directories that contain auto generated code, like Smarty or ZFW cache.
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2) Code that does not work well when accelerated, due to some delayed
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compile time evaluation.
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3) Code that triggers an OPcache bug.
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opcache.max_file_size (default "0")
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Allows exclusion of large files from being cached. By default all files
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are cached.
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opcache.consistency_checks (default "0")
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Check the cache checksum each N requests.
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The default value of "0" means that the checks are disabled.
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Because calculating the checksum impairs performance, this directive should
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be enabled only as part of a debugging process.
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opcache.force_restart_timeout (default "180")
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How long to wait (in seconds) for a scheduled restart to begin if the cache
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is not being accessed.
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The OPcache uses this directive to identify a situation where there may
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be a problem with a process. After this time period has passed, the
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OPcache assumes that something has happened and starts killing the
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processes that still hold the locks that are preventing a restart.
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If the log level is 3 or above, a "killed locker" error is recorded
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in the Apache logs when this happens.
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opcache.error_log
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OPcache error_log file name. Empty string assumes "stderr".
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opcache.log_verbosity_level (default "1")
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All OPcache errors go to the Web server log.
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By default, only fatal errors (level 0) or errors (level 1) are logged.
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You can also enable warnings (level 2), info messages (level 3) or
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debug messages (level 4).
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opcache.preferred_memory_model
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Preferred Shared Memory back-end. Leave empty and let the system decide.
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opcache.protect_memory (default "0")
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Protect the shared memory from unexpected writing during script execution.
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Useful for internal debugging only.
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opcache.restrict_api (default "")
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Allows calling OPcache API functions only from PHP scripts which path is
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started from specified string. The default "" means no restriction.
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opcache.mmap_base
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Mapping base of shared memory segments (for Windows only). All the PHP
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processes have to map shared memory into the same address space. This
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directive allows to manually fix the "Unable to reattach to base address"
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errors.
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