1The Zend OPcache 2================ 3 4The Zend OPcache provides faster PHP execution through opcode caching and 5optimization. It improves PHP performance by storing precompiled script 6bytecode in the shared memory. This eliminates the stages of reading code from 7the disk and compiling it on future access. In addition, it applies a few 8bytecode optimization patterns that make code execution faster. 9 10Compatibility 11------------- 12 13This version of Zend OPcache is compatible with PHP 5.2.*, 5.3.*, 5.4.* 14and PHP-5.5 development branch. PHP 5.2 support may be removed in the future. 15 16Quick Install 17------------- 18 19- Compile 20 21 $PHP_DIR/bin/phpize 22 ./configure \ 23 --with-php-config=$PHP_DIR/bin/php-config 24 make 25 26- Install 27 28 make install # this will copy opcache.so into PHP extension directory 29 30- Edit php.ini 31 32 zend_extension=/...full path.../opcache.so 33 34NOTE: In case you are going to use Zend OPcache together with Xdebug or Zend Debugger, 35be sure that the debugger is loaded after OPcache. "php -v" must show the debugger 36after OPcache. 37 38- Restart PHP 39 40Speed Tuning 41------------- 42 43We recommend the following configuration options for best performance 44in a production environment. 45 46opcache.memory_consumption=128 47opcache.interned_strings_buffer=8 48opcache.max_accelerated_files=4000 49opcache.revalidate_freq=60 50opcache.fast_shutdown=1 51opcache.enable_cli=1 52 53You also may add the following, but it may break some applications and 54frameworks. Please, read description of these directives and add them on your 55own risk. 56 57opcache.save_comments=0 58opcache.enable_file_override=1 59 60In some cases you may like to prefer enabling/disabling some features 61to avoid incompatibilities at the cost of some performance degradation. 62 63For development environment we would recommend setting opcache.revalidate_freq 64into 0. 65 66Configuration Directives 67------------------------ 68 69opcache.enable (default "1") 70 OPcache On/Off switch. When set to Off, code is not optimized and cached. 71 72opcache.enable_cli (default "0") 73 Enables the OPcache for the CLI version of PHP. It's mostly for testing 74 and debugging. 75 76opcache.memory_consumption (default "64") 77 The OPcache shared memory storage size. The amount of memory for storing 78 precompiled PHP code in Mbytes. 79 80opcache.interned_strings_buffer (default "4") 81 The amount of memory for interned strings in Mbytes. 82 83opcache.max_accelerated_files (default "2000") 84 The maximum number of keys (scripts) in the OPcache hash table. 85 The number is actually the first one in the following set of prime 86 numbers that is bigger than the one supplied: { 223, 463, 983, 1979, 3907, 87 7963, 16229, 32531, 65407, 130987, 262237, 524521, 1048793 }. Only numbers 88 between 200 and 1000000 are allowed. 89 90opcache.max_wasted_percentage (default "5") 91 The maximum percentage of "wasted" memory until a restart is scheduled. 92 93opcache.use_cwd (default "1") 94 When this directive is enabled, the OPcache appends the current working 95 directory to the script key, thus eliminating possible collisions between 96 files with the same name (basename). Disabling the directive improves 97 performance, but may break existing applications. 98 99opcache.validate_timestamps (default "1") 100 When disabled, you must reset the OPcache manually or restart the 101 webserver for changes to the filesystem to take effect. 102 The frequency of the check is controlled by the directive 103 "opcache.revalidate_freq". 104 105opcache.revalidate_freq (default "2") 106 How often (in seconds) to check file timestamps for changes to the shared 107 memory storage allocation. ("1" means validate once per second, but only 108 once per request. "0" means always validate) 109 110opcache.file_update_protection (default "2") 111 Prevents caching files that are less than this number of seconds old. 112 It protects from caching of incompletely updated files. In case all file 113 updates on your site are atomic, you may increase performance setting it 114 to "0". 115 116opcache.revalidate_path (default "0") 117 Enables or disables file search in include_path optimization 118 If the file search is disabled and a cached file is found that uses 119 the same include_path, the file is not searched again. Thus, if a file 120 with the same name appears somewhere else in include_path, it 121 won't be found. Enable this directive if this optimization has an effect on 122 your applications. The default for this directive is disabled, which means 123 that optimization is active. 124 125opcache.save_comments (default "1") 126 If disabled, all PHPDoc comments are dropped from the code to reduce the 127 size of the optimized code. Disabling "Doc Comments" may break some 128 existing applications and frameworks (e.g. Doctrine, ZF2, PHPUnit) 129 130opcache.load_comments (default "1") 131 If disabled, PHPDoc comments are not loaded from SHM, so "Doc Comments" 132 may be always stored (save_comments=1), but not loaded by applications 133 that don't need them anyway. 134 135opcache.fast_shutdown (default "0") 136 If enabled, a fast shutdown sequence is used for the accelerated code 137 The fast shutdown sequence doesn't free each allocated block, but lets 138 the Zend Engine Memory Manager do the work. 139 140opcache.enable_file_override (default "0") 141 Allow file existence override (file_exists, etc.) performance feature. 142 143opcache.optimization_level (default "0xffffffff") 144 A bitmask, where each bit enables or disables the appropriate OPcache 145 passes 146 147opcache.inherited_hack (default "1") 148 Enable this hack as a workaround for "can't redeclare class" errors. 149 The OPcache stores the places where DECLARE_CLASS opcodes use 150 inheritance (These are the only opcodes that can be executed by PHP, 151 but which may not be executed because the parent class is missing due to 152 optimization). When the file is loaded, OPcache tries to bind the 153 inherited classes by using the current environment. The problem with this 154 scenario is that, while the DECLARE_CLASS opcode may not be needed for the 155 current script, if the script requires that the opcode at least be defined, 156 it may not run. The default for this directive is disabled, which means 157 that optimization is active. In php-5.3 and above this hack is not needed 158 anymore and this setting has no effect. 159 160opcache.dups_fix (default "0") 161 Enable this hack as a workaround for "Cannot redeclare class" errors. 162 163opcache.blacklist_filename 164 The location of the OPcache blacklist file (wildcards allowed). 165 Each OPcache blacklist file is a text file that holds the names of files 166 that should not be accelerated. The file format is to add each filename 167 to a new line. The filename may be a full path or just a file prefix 168 (i.e., /var/www/x blacklists all the files and directories in /var/www 169 that start with 'x'). Line starting with a ; are ignored (comments). 170 Files are usually triggered by one of the following three reasons: 171 1) Directories that contain auto generated code, like Smarty or ZFW cache. 172 2) Code that does not work well when accelerated, due to some delayed 173 compile time evaluation. 174 3) Code that triggers an OPcache bug. 175 176opcache.max_file_size (default "0") 177 Allows exclusion of large files from being cached. By default all files 178 are cached. 179 180opcache.consistency_checks (default "0") 181 Check the cache checksum each N requests. 182 The default value of "0" means that the checks are disabled. 183 Because calculating the checksum impairs performance, this directive should 184 be enabled only as part of a debugging process. 185 186opcache.force_restart_timeout (default "180") 187 How long to wait (in seconds) for a scheduled restart to begin if the cache 188 is not being accessed. 189 The OPcache uses this directive to identify a situation where there may 190 be a problem with a process. After this time period has passed, the 191 OPcache assumes that something has happened and starts killing the 192 processes that still hold the locks that are preventing a restart. 193 If the log level is 3 or above, a "killed locker" error is recorded 194 in the Apache logs when this happens. 195 196opcache.error_log 197 OPcache error_log file name. Empty string assumes "stderr". 198 199opcache.log_verbosity_level (default "1") 200 All OPcache errors go to the Web server log. 201 By default, only fatal errors (level 0) or errors (level 1) are logged. 202 You can also enable warnings (level 2), info messages (level 3) or 203 debug messages (level 4). 204 205opcache.preferred_memory_model 206 Preferred Shared Memory back-end. Leave empty and let the system decide. 207 208opcache.protect_memory (default "0") 209 Protect the shared memory from unexpected writing during script execution. 210 Useful for internal debugging only. 211 212opcache.restrict_api (default "") 213 Allows calling OPcache API functions only from PHP scripts which path is 214 started from specified string. The default "" means no restriction. 215 216opcache.mmap_base 217 Mapping base of shared memory segments (for Windows only). All the PHP 218 processes have to map shared memory into the same address space. This 219 directive allows to manually fix the "Unable to reattach to base address" 220 errors. 221
