rfc:fibers

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision
Previous revision
Next revisionBoth sides next revision
rfc:fibers [2021/03/08 18:09] – Update intro kelunikrfc:fibers [2021/03/11 23:32] – Add note about future internal fiber API trowski
Line 3: Line 3:
   * Date: 2021-03-08   * Date: 2021-03-08
   * Authors: Aaron Piotrowski <trowski@php.net>, Niklas Keller <kelunik@php.net>   * Authors: Aaron Piotrowski <trowski@php.net>, Niklas Keller <kelunik@php.net>
-  * Status: Under Discussion+  * Status: Voting
   * First Published at: http://wiki.php.net/rfc/fibers   * First Published at: http://wiki.php.net/rfc/fibers
  
Line 27: Line 27:
   * Adding a ''Fiber'' class and the corresponding reflection class ''ReflectionFiber''.   * Adding a ''Fiber'' class and the corresponding reflection class ''ReflectionFiber''.
   * Adding exception classes ''FiberError'' and ''FiberExit'' to represent errors.   * Adding exception classes ''FiberError'' and ''FiberExit'' to represent errors.
 +
 +Fibers allow for transparent non-blocking I/O implementations of existing interfaces (such as PSR-7, Doctine ORM, etc.). This is because the placeholder (promise) object is eliminated. Functions instead can declare the I/O result type instead of a placeholder object which cannot specify a resolution type because PHP does not support generics.
  
 ==== Fibers ==== ==== Fibers ====
Line 220: Line 222:
 === Fiber Stacks === === Fiber Stacks ===
  
-Each fiber is allocated a separate C stack and VM stack on the heap. The C stack is allocated using ''mmap'' if available, meaning physical memory is used only on demand (if it needs to be allocated to a stack value) on most platforms. Each fiber stack is allocated a maximum of 8M if memory by default, settable with an ini setting ''fiber.stack_size''. Note that this memory is used for the C stack and is not related to the memory available to PHP code. VM stacks for each fiber are allocated in a similar way to generators and use a similar amount of memory and CPU. VM stacks are able to grow dynamically, so only a single VM page (4K) is initially allocated.+Each fiber is allocated a separate C stack and VM stack on the heap. The C stack is allocated using ''mmap'' if available, meaning physical memory is used only on demand (if it needs to be allocated to a stack value) on most platforms. Each fiber stack is allocated a maximum of 8M of memory by default, settable with an ini setting ''fiber.stack_size''. Note that this memory is used for the C stack and is not related to the memory available to PHP code. VM stacks for each fiber are allocated in a similar way to generators and use a similar amount of memory and CPU. VM stacks are able to grow dynamically, so only a single VM page (4K) is initially allocated.
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
  
 Declares ''Fiber'', ''FiberError'', ''FiberExit'', and ''ReflectionFiber'' in the root namespace. No other BC breaks. Declares ''Fiber'', ''FiberError'', ''FiberExit'', and ''ReflectionFiber'' in the root namespace. No other BC breaks.
- 
-===== Proposed PHP Version(s) ===== 
- 
-PHP 8.1 
  
 ===== Future Scope ===== ===== Future Scope =====
  
-=== suspend keyword ===+The current implementation does not provide an internal API for fibers for PHP extensions. This RFC focuses on the user space fiber API. An internal fiber API will be added, collaborating with other internal developers and using feedback from PHP extension developers, including Swoole, so fibers can be created and controlled from PHP extensions. An extension may still optionally provide their own custom fiber implementation, but an internal API would allow the extension to use the fiber implementation provided by PHP.
  
-''Fiber::suspend()'' could be replaced with a keyword ''suspend'' that would be similar to ''yield''. The keyword statement would accept an optional expression that would be the suspend value and return the value used to resume the fiber.+===== Proposed PHP Version(s=====
  
-//variable// **= suspend** //expression//**;**+PHP 8.1
  
 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
Line 566: Line 564:
 It is the opinion of the authors of this RFC that it is best to provide the bare minimum in core and allow user code to implement other components as they desire. If the community moves toward a single event loop API or a need emerges for an event loop in PHP core, this can be done in a future RFC. Providing a core event loop without core functionality using it (such as streams, file access, etc.) would be misleading and confusing for users. Deferring such functionality to user frameworks and providing only a minimum API in core keeps expectations in check. It is the opinion of the authors of this RFC that it is best to provide the bare minimum in core and allow user code to implement other components as they desire. If the community moves toward a single event loop API or a need emerges for an event loop in PHP core, this can be done in a future RFC. Providing a core event loop without core functionality using it (such as streams, file access, etc.) would be misleading and confusing for users. Deferring such functionality to user frameworks and providing only a minimum API in core keeps expectations in check.
  
-This RFC does not preclude adding async/await and an event loop to core, see [[#future_scope|Future Scope]].+This RFC does not preclude adding async/await and an event loop to core.
  
 === How does this proposal differ from prior Fiber proposals? === === How does this proposal differ from prior Fiber proposals? ===
Line 583: Line 581:
  
 As noted in [[#why_add_this_to_php_core|“Why add this to PHP core?”]], extensions that profile code, create backtraces, provide execution times, etc. will need to be updated to account for switching between fibers to provide correct data. As noted in [[#why_add_this_to_php_core|“Why add this to PHP core?”]], extensions that profile code, create backtraces, provide execution times, etc. will need to be updated to account for switching between fibers to provide correct data.
 +
 +===== Vote =====
 +
 +Voting started on 2021-03-08 and will run through 2021-03-22. 2/3 required to accept.
 +
 +<doodle title="Add Fibers to PHP?" auth="trowski" voteType="single" closed="false">
 +   * Yes
 +   * No
 +</doodle>
  
 ===== References ===== ===== References =====
rfc/fibers.txt · Last modified: 2021/07/12 21:30 by kelunik