Preemptive multitasking using coroutines in PHP Swoole

PHP Swoole enables PHP developers to write high-performance, scalable, concurrent TCP, UDP, Unix socket, HTTP, WebSocket services in PHP programming language.

Compared with other async programming frameworks or software such as Nginx, Tornado, Node.js, Swoole has the built-in async, coroutines, multiple threads I/O modules.

Preemptive scheduling is the key to building a high performance, low latency, near the real-time system.

Compared with other programming languages or frameworks, PHP Swoole is one of the very few supports preemptive multitasking using coroutines.

This talk we like to introduce the coroutines in PHP Swoole and the implementation of a multitasking coroutines scheduler in PHP Swoole.

Transcript

1. Preemptive multitasking using
   coroutines in PHP Swoole
   Bruce Dou | @doubaokun
   bruce@transfon.com
   6th Jun 2019
   

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2. 1. Evolution of web server or services
   2. The problems to solve for PHP
   3. Coroutinesand preemptive schedulingfor PHP
   4. Show case preemptivescheduling in PHP Swoole
   Agenda
   

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3. About me
   • Software Architect & Head of Development
   • Founderat Transfon
   • Twitter:@doubaokun
   • Email:bruce@transfon.com
   • Linkedin:linkedin.com/in/brucedou
   • Github: github.com/doubaokun
   

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4. Security
   Performance
   Regulation compliance
   Cost control
   About Transfon
   

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5. Evolution of web server or services
   

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7. https://unixism.net/2019/04/linux-applications-performance-introduction/
   

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8. I/O bound vs CPU bound
   

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9. Decoupling I/O and Computation
   

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10. Async and non-blocking I/O
    

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11. Why non-blocking I/O matters
    Multiple cores and fast CPU vs slow Network I/O
    

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12. Linux I/O multiplexing, non-blocking
    • select() monitors the sockets’ status flag and return the status
    of all sockets, manually iterate through all the fds (C10K problem)
    • poll() similar to select() but allocate an array of pollfd, can
    handle more than 1024 sockets
    •epoll() monitors sockets’ status and trigger related events,
    and only return triggered events array.
    

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13. Reactor pattern
    

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14. PHP ?
    

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15. The problems to solve for PHP
    • High concurrency,large numberof connections
    • Long-liveconnections,real-timeservices
    • Long-liveconnectionsto DB, Cache, RPC etc
    • Supportmoreprotocols
    • Server programming,not just scripts
    • Milliseconds scheduler
    • Async tasks of consuming3rd party services
    • Manage and reuse the statusin memory
    • Performance
    

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17. 1.Receive the request
    2.Load and compile PHP files and codes
    3.Initialize the context objects and variables
    4.Execute the functions
    5.Send the response
    6.Recycle the resources
    The life cycle of HTTP request in PHP-FPM
    

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18. 1.Load and compile files and codes
    2.Initialize the context objects and variables
    3.Receive the request
    4.Execute the functions
    5.Send the response
    6.Recycle the resources
    The life cycle of HTTP request in PHP Swoole
    

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19. PHP Swoole
    https://www.swoole.co.uk/
    https://github.com/swoole/swoole-src
    @php_swoole
    Coroutine-based concurrency library for PHP
    

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20. Get started
    git clone git@github.com:doubaokun/phplondon201906.git
    docker build -f Dockerfile -t swoole-phplondon .
    docker run --rm -p 9501:9501 -v $(pwd):/app -w /app \
    swoole-phplondon server.php
    

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21. How it looks like
    

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22. How fast
    

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23. Open Source(Apache2 license)
    PHP Extension
    C/C++ / Boost.Context
    Callbackstyle & Coroutine
    Event-basednon-blockingI/O
    HTTP/HTTP2/Websocket/TCP/UDPetc
    Milliseconds task scheduler
    Process manager
    Preemptivescheduling
    PHP Swoole
    

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24. The problems we like to solve further
    • Callback hell
    • Use Coroutinestyle (sync) concurrency
    • Automaticallycontextswitchbasedon I/O
    • Soft real-time
    • Long tail latency
    • One bad guy stopthe world
    

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25. Callback hell
    

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26. Callback hell
    Swoole 2.x.x
    

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27. I/O based automatically
    scheduling in PHP Swoole
    

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28. I/O based automatically scheduling
    

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29. Coroutines in PHP Swoole
    

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30. Coroutines in PHP Swoole
    

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31. Problem with CPU heavy business logics
    

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32. Preemptive scheduling
    

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33. PHP Swoole Server
    

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34. HTTP server with PHP Swoole
    

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36. HTTP server structure
    

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37. Preemptive scheduling in PHP Swoole Server
    

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38. Scheduling thread
    ZendVM:EG(vm_interrupt)= 1
    Zend_interrupt_function
    Yield current coroutineif it runs longer than 5ms
    How preemptive scheduling works
    

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39. Preemptive scheduling in PHP Swoole Server
    

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40. HTTP server structure single process
    

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41. Preemptive scheduling in PHP Swoole Server
    time curl -I http://127.0.0.1:9501/\?p\=1 (CPU heavy logics)
    time curl -I http://127.0.0.1:9501/\?p\=0 (light weight logics)
    docker run --rm -p 9501:9501 -v $(pwd):/app -w /app \
    swoole-phplondon server_preemptive.php
    time curl -I http://127.0.0.1:9501/\?p\=1 & sleep 1 && \
    time curl -I http://127.0.0.1:9501/\?p\=0 & wait
    

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42. Preemptive scheduling in PHP Swoole Server
    ini_set("swoole.enable_preemptive_scheduler", "0");
    

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43. Preemptive scheduling in PHP Swoole Server
    ini_set("swoole.enable_preemptive_scheduler", "1");
    

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44. Real world meaningof preemptive scheduling
    

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45. Real-world meaning of preemptive scheduling
    

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46. https://github.com/doubaokun/phplondon201906
    https://www.swoole.co.uk/
    https://github.com/swoole/swoole-src
    https://swoole.slack.com
    https://twitter.com/php_swoole
    Thank you
    

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