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.enable_cli=1 51 52You also may add the following, but it may break some applications and 53frameworks. Please, read description of these directives and add them on your 54own risk. 55 56opcache.save_comments=0 57opcache.enable_file_override=1 58 59In some cases you may like to prefer enabling/disabling some features 60to avoid incompatibilities at the cost of some performance degradation. 61 62For development environment we would recommend setting opcache.revalidate_freq 63into 0. 64 65Configuration Directives 66------------------------ 67 68opcache.enable (default "1") 69 OPcache On/Off switch. When set to Off, code is not optimized and cached. 70 71opcache.enable_cli (default "0") 72 Enables the OPcache for the CLI version of PHP. It's mostly for testing 73 and debugging. 74 75opcache.memory_consumption (default "64") 76 The OPcache shared memory storage size. The amount of memory for storing 77 precompiled PHP code in Mbytes. 78 79opcache.interned_strings_buffer (default "4") 80 The amount of memory for interned strings in Mbytes. 81 82opcache.max_accelerated_files (default "2000") 83 The maximum number of keys (scripts) in the OPcache hash table. 84 The number is actually the first one in the following set of prime 85 numbers that is bigger than the one supplied: { 223, 463, 983, 1979, 3907, 86 7963, 16229, 32531, 65407, 130987, 262237, 524521, 1048793 }. Only numbers 87 between 200 and 1000000 are allowed. 88 89opcache.max_wasted_percentage (default "5") 90 When the cache fills up this setting decides when to actually reset (dump 91 all entries) it. At the default of 5% it means that if less than 5% of 92 the entries in the now full cache are wasted/orphaned, then you have a good 93 active cache. There is no point emptying a cache full of good entries 94 only to most likely refill it with those same entries. Once more than 5% 95 of the cache consists of wasted entries, the cache will reset in this 96 cache-full scenario. This can be set up to as high as 50%. 97 98opcache.use_cwd (default "1") 99 When this directive is enabled, the OPcache appends the current working 100 directory to the script key, thus eliminating possible collisions between 101 files with the same name (basename). Disabling the directive improves 102 performance, but may break existing applications. 103 104opcache.validate_timestamps (default "1") 105 When disabled, you must reset the OPcache manually or restart the 106 webserver for changes to the filesystem to take effect. 107 The frequency of the check is controlled by the directive 108 "opcache.revalidate_freq". 109 110opcache.validate_permission (default "0") 111 Leads OPcache to check file readability on each access to cached file. 112 This directive should be enabled in shared hosting environment, when few 113 users (PHP-FPM pools) reuse the common OPcache shared memory. 114 115opcache.validate_root (default "0") 116 This directive prevents file name collisions in different "chroot" 117 environments. It should be enabled for sites that may serve requests in 118 different "chroot" environments. 119 120opcache.revalidate_freq (default "2") 121 How often (in seconds) to check file timestamps for changes to the shared 122 memory storage allocation. ("1" means validate once per second, but only 123 once per request. "0" means always validate) 124 125opcache.file_update_protection (default "2") 126 Prevents caching files that are less than this number of seconds old. 127 It protects from caching of incompletely updated files. In case all file 128 updates on your site are atomic, you may increase performance setting it 129 to "0". 130 131opcache.revalidate_path (default "0") 132 Enables or disables file search in include_path optimization 133 If the file search is disabled and a cached file is found that uses 134 the same include_path, the file is not searched again. Thus, if a file 135 with the same name appears somewhere else in include_path, it 136 won't be found. Enable this directive if this optimization has an effect on 137 your applications. The default for this directive is disabled, which means 138 that optimization is active. 139 140opcache.save_comments (default "1") 141 If disabled, all PHPDoc comments are dropped from the code to reduce the 142 size of the optimized code. Disabling "Doc Comments" may break some 143 existing applications and frameworks (e.g. Doctrine, ZF2, PHPUnit) 144 145opcache.enable_file_override (default "0") 146 Allow file existence override (file_exists, etc.) performance feature. 147 148opcache.optimization_level (default "0xffffffff") 149 A bitmask, where each bit enables or disables the appropriate OPcache 150 passes 151 152opcache.inherited_hack (default "1") 153 Enable this hack as a workaround for "Cannot redeclare class" errors. 154 The OPcache stores the places where DECLARE_CLASS opcodes use 155 inheritance (These are the only opcodes that can be executed by PHP, 156 but which may not be executed because the parent class is missing due to 157 optimization). When the file is loaded, OPcache tries to bind the 158 inherited classes by using the current environment. The problem with this 159 scenario is that, while the DECLARE_CLASS opcode may not be needed for the 160 current script, if the script requires that the opcode at least be defined, 161 it may not run. The default for this directive is disabled, which means 162 that optimization is active. In php-5.3 and above this hack is not needed 163 anymore and this setting has no effect. 164 165opcache.dups_fix (default "0") 166 Enable this hack as a workaround for "Cannot redeclare class" errors. 167 168opcache.blacklist_filename 169 The location of the OPcache blacklist file (wildcards allowed). 170 Each OPcache blacklist file is a text file that holds the names of files 171 that should not be accelerated. The file format is to add each filename 172 to a new line. The filename may be a full path or just a file prefix 173 (i.e., /var/www/x blacklists all the files and directories in /var/www 174 that start with 'x'). Line starting with a ; are ignored (comments). 175 Files are usually triggered by one of the following three reasons: 176 1) Directories that contain auto generated code, like Smarty or ZFW cache. 177 2) Code that does not work well when accelerated, due to some delayed 178 compile time evaluation. 179 3) Code that triggers an OPcache bug. 180 181opcache.max_file_size (default "0") 182 Allows exclusion of large files from being cached. By default all files 183 are cached. 184 185opcache.consistency_checks (default "0") 186 Check the cache checksum each N requests. 187 The default value of "0" means that the checks are disabled. 188 Because calculating the checksum impairs performance, this directive should 189 be enabled only as part of a debugging process. 190 191opcache.force_restart_timeout (default "180") 192 How long to wait (in seconds) for a scheduled restart to begin if the cache 193 is not being accessed. 194 The OPcache uses this directive to identify a situation where there may 195 be a problem with a process. After this time period has passed, the 196 OPcache assumes that something has happened and starts killing the 197 processes that still hold the locks that are preventing a restart. 198 If the log level is 3 or above, a "killed locker" error is recorded 199 in the Apache logs when this happens. 200 201opcache.error_log 202 OPcache error_log file name. Empty string assumes "stderr". 203 204opcache.log_verbosity_level (default "1") 205 All OPcache errors go to the Web server log. 206 By default, only fatal errors (level 0) or errors (level 1) are logged. 207 You can also enable warnings (level 2), info messages (level 3) or 208 debug messages (level 4). 209 210opcache.preferred_memory_model 211 Preferred Shared Memory back-end. Leave empty and let the system decide. 212 213opcache.protect_memory (default "0") 214 Protect the shared memory from unexpected writing during script execution. 215 Useful for internal debugging only. 216 217opcache.restrict_api (default "") 218 Allows calling OPcache API functions only from PHP scripts which path is 219 started from specified string. The default "" means no restriction. 220 221opcache.mmap_base 222 Mapping base of shared memory segments (for Windows only). All the PHP 223 processes have to map shared memory into the same address space. This 224 directive allows to manually fix the "Unable to reattach to base address" 225 errors. 226 227opcache.lockfile_path (default "/tmp") 228 Absolute path used to store shared lockfiles (for *nix only) 229
