rfc:preload
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rfc:preload [2018/10/22 09:06] – Fix typos etc nikic | rfc:preload [2018/11/21 22:35] – This RFC has already been implemented cmb | ||
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* Date: 2018-10-18 | * Date: 2018-10-18 | ||
* Author: Dmitry Stogov, dmitry@zend.com | * Author: Dmitry Stogov, dmitry@zend.com | ||
- | * Status: | + | * Status: |
* First Published at: http:// | * First Published at: http:// | ||
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As mentioned above, preloaded files remain cached in opcache memory forever. Modification of their corresponding source files won't have any effect without another server restart. All functions and most classes defined in these files will be permanently loaded into PHP's function and class tables and become permanently available in the context of any future request. During preloading, PHP also resolves class dependencies and links with parent, interfaces and traits. It also removes unnecessary includes and performs some other optimizations. | As mentioned above, preloaded files remain cached in opcache memory forever. Modification of their corresponding source files won't have any effect without another server restart. All functions and most classes defined in these files will be permanently loaded into PHP's function and class tables and become permanently available in the context of any future request. During preloading, PHP also resolves class dependencies and links with parent, interfaces and traits. It also removes unnecessary includes and performs some other optimizations. | ||
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+ | '' | ||
+ | |||
+ | '' | ||
+ | |||
+ | ==== Static members and static variables ==== | ||
+ | To avoid misunderstanding, | ||
==== Preloading Limitation ==== | ==== Preloading Limitation ==== | ||
Only classes without unresolved parent, interfaces, traits and constant values may be preloaded. | Only classes without unresolved parent, interfaces, traits and constant values may be preloaded. | ||
- | Also, only top-level entities that are not nested within control structures (e.g. if()...) may be preloaded. | + | Also, only top-level entities that are not nested within control structures (e.g. if()...) may be preloaded. |
+ | |||
+ | On Windows, it's also not possible to preload classes inherited from internal ones. Windows ASLR and absence of fork() don't allow to guarantee the same addresses of internal classes in different processes. | ||
==== Implementation Details ==== | ==== Implementation Details ==== | ||
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==== php.ini Defaults ==== | ==== php.ini Defaults ==== | ||
* opcache.preload - specifies a PHP script that is going to be compiled and executed at server start-up. | * opcache.preload - specifies a PHP script that is going to be compiled and executed at server start-up. | ||
- | |||
- | ===== Open Issues ===== | ||
- | * preloading in ZTS build is not supported yet | ||
===== Performance ===== | ===== Performance ===== | ||
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* In conjunction with ext/FFI (dangerous extension), we may allow FFI functionality only in preloaded PHP files, but not in regular ones | * In conjunction with ext/FFI (dangerous extension), we may allow FFI functionality only in preloaded PHP files, but not in regular ones | ||
* It's possible to perform more aggressive optimizations and generate better JIT code for preloaded functions and classes (similar to HHVM Repo Authoritative mode in HHVM) | * It's possible to perform more aggressive optimizations and generate better JIT code for preloaded functions and classes (similar to HHVM Repo Authoritative mode in HHVM) | ||
+ | * It would be great, to extend preloading with some kind of deployment mechanism, to update preloaded bundle(s) without server restart. | ||
===== Proposed Voting Choices ===== | ===== Proposed Voting Choices ===== | ||
- | The RFC requires 50%+1 majority | + | The RFC requires 50%+1 majority. The voting started **2018-11-06** and will close on **2018-11-14** |
+ | |||
+ | <doodle title=" | ||
+ | * Yes | ||
+ | * No | ||
+ | </ | ||
===== Patches and Tests ===== | ===== Patches and Tests ===== | ||
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===== Implementation ===== | ===== Implementation ===== | ||
After the project is implemented, | After the project is implemented, | ||
- | - the version(s) it was merged into | + | - merged into 7.4 |
- | - a link to the git commit(s) | + | - git commit |
- a link to the PHP manual entry for the feature | - a link to the PHP manual entry for the feature | ||
- | - a link to the language specification section (if any) | ||
===== References ===== | ===== References ===== | ||
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* [[https:// | * [[https:// | ||
* [[https:// | * [[https:// | ||
- | |||
- | ===== Rejected Features ===== | ||
- | Keep this updated with features that were discussed on the mail lists. |
rfc/preload.txt · Last modified: 2019/01/21 18:20 by cmb