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.validate_permission (default "0") 106 Leads OPcache to check file readability on each access to cached file. 107 This directive should be enabled in shared hosting environment, when few 108 users (PHP-FPM pools) reuse the common OPcache shared memory. 109 110opcache.validate_root (default "0") 111 This directive prevents file name collisions in different "chroot" 112 environments. It should be enabled for sites that may serve requests in 113 different "chroot" environments. 114 115opcache.revalidate_freq (default "2") 116 How often (in seconds) to check file timestamps for changes to the shared 117 memory storage allocation. ("1" means validate once per second, but only 118 once per request. "0" means always validate) 119 120opcache.file_update_protection (default "2") 121 Prevents caching files that are less than this number of seconds old. 122 It protects from caching of incompletely updated files. In case all file 123 updates on your site are atomic, you may increase performance setting it 124 to "0". 125 126opcache.revalidate_path (default "0") 127 Enables or disables file search in include_path optimization 128 If the file search is disabled and a cached file is found that uses 129 the same include_path, the file is not searched again. Thus, if a file 130 with the same name appears somewhere else in include_path, it 131 won't be found. Enable this directive if this optimization has an effect on 132 your applications. The default for this directive is disabled, which means 133 that optimization is active. 134 135opcache.save_comments (default "1") 136 If disabled, all PHPDoc comments are dropped from the code to reduce the 137 size of the optimized code. Disabling "Doc Comments" may break some 138 existing applications and frameworks (e.g. Doctrine, ZF2, PHPUnit) 139 140opcache.load_comments (default "1") 141 If disabled, PHPDoc comments are not loaded from SHM, so "Doc Comments" 142 may be always stored (save_comments=1), but not loaded by applications 143 that don't need them anyway. 144 145opcache.fast_shutdown (default "0") 146 If enabled, a fast shutdown sequence is used for the accelerated code 147 The fast shutdown sequence doesn't free each allocated block, but lets 148 the Zend Engine Memory Manager do the work. 149 150opcache.enable_file_override (default "0") 151 Allow file existence override (file_exists, etc.) performance feature. 152 153opcache.optimization_level (default "0xffffffff") 154 A bitmask, where each bit enables or disables the appropriate OPcache 155 passes 156 157opcache.inherited_hack (default "1") 158 Enable this hack as a workaround for "can't redeclare class" errors. 159 The OPcache stores the places where DECLARE_CLASS opcodes use 160 inheritance (These are the only opcodes that can be executed by PHP, 161 but which may not be executed because the parent class is missing due to 162 optimization). When the file is loaded, OPcache tries to bind the 163 inherited classes by using the current environment. The problem with this 164 scenario is that, while the DECLARE_CLASS opcode may not be needed for the 165 current script, if the script requires that the opcode at least be defined, 166 it may not run. The default for this directive is disabled, which means 167 that optimization is active. In php-5.3 and above this hack is not needed 168 anymore and this setting has no effect. 169 170opcache.dups_fix (default "0") 171 Enable this hack as a workaround for "Cannot redeclare class" errors. 172 173opcache.blacklist_filename 174 The location of the OPcache blacklist file (wildcards allowed). 175 Each OPcache blacklist file is a text file that holds the names of files 176 that should not be accelerated. The file format is to add each filename 177 to a new line. The filename may be a full path or just a file prefix 178 (i.e., /var/www/x blacklists all the files and directories in /var/www 179 that start with 'x'). Line starting with a ; are ignored (comments). 180 Files are usually triggered by one of the following three reasons: 181 1) Directories that contain auto generated code, like Smarty or ZFW cache. 182 2) Code that does not work well when accelerated, due to some delayed 183 compile time evaluation. 184 3) Code that triggers an OPcache bug. 185 186opcache.max_file_size (default "0") 187 Allows exclusion of large files from being cached. By default all files 188 are cached. 189 190opcache.consistency_checks (default "0") 191 Check the cache checksum each N requests. 192 The default value of "0" means that the checks are disabled. 193 Because calculating the checksum impairs performance, this directive should 194 be enabled only as part of a debugging process. 195 196opcache.force_restart_timeout (default "180") 197 How long to wait (in seconds) for a scheduled restart to begin if the cache 198 is not being accessed. 199 The OPcache uses this directive to identify a situation where there may 200 be a problem with a process. After this time period has passed, the 201 OPcache assumes that something has happened and starts killing the 202 processes that still hold the locks that are preventing a restart. 203 If the log level is 3 or above, a "killed locker" error is recorded 204 in the Apache logs when this happens. 205 206opcache.error_log 207 OPcache error_log file name. Empty string assumes "stderr". 208 209opcache.log_verbosity_level (default "1") 210 All OPcache errors go to the Web server log. 211 By default, only fatal errors (level 0) or errors (level 1) are logged. 212 You can also enable warnings (level 2), info messages (level 3) or 213 debug messages (level 4). 214 215opcache.preferred_memory_model 216 Preferred Shared Memory back-end. Leave empty and let the system decide. 217 218opcache.protect_memory (default "0") 219 Protect the shared memory from unexpected writing during script execution. 220 Useful for internal debugging only. 221 222opcache.restrict_api (default "") 223 Allows calling OPcache API functions only from PHP scripts which path is 224 started from specified string. The default "" means no restriction. 225 226opcache.mmap_base 227 Mapping base of shared memory segments (for Windows only). All the PHP 228 processes have to map shared memory into the same address space. This 229 directive allows to manually fix the "Unable to reattach to base address" 230 errors. 231
