Coroutine Based Concurrency with PHP and Swoole

PHP Swoole has gained traction during the past several years. More and more people are interested with started to try PHP Swoole and use coroutine in PHP to build high performance, large scale web services, online game, micro-services.

Transcript

1. Coroutine Based Concurrency with
   PHP and Swoole
   Bruce Dou | @doubaokun
   bruce@transfon.com
   20th Feb 2020 PHPUK2020
   

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2. About me
   • Founder at Transfon
   • Twitter: @doubaokun
   • Email: bruce@transfon.com
   • Linkedin: linkedin.com/in/brucedou
   • Github: github.com/doubaokun
   Twitter: @doubaokun
   

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3. Agenda
   • Rethinking about software development
   • Concurrency, I/O, Scheduling and OS
   • Coroutine: Cooperative multi-tasking
   • Swoole Coroutine Internal
   • Swoole
   • Coroutine and Swoole code samples
   • Demo
   Twitter: @doubaokun
   

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4. Rethinking about software development
   Twitter: @doubaokun
   

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5. Twitter: @doubaokun
   Mapping real world problems onto machine
   

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6. Execution Unit
   Twitter: @doubaokun
   

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7. I/O and Task Processing
   Twitter: @doubaokun
   

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8. Twitter: @doubaokun
   

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9. Twitter: @doubaokun
   Mapping real world problems onto machine
   with several levels abstraction
   

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10. Twitter: @doubaokun
    

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11. Twitter: @doubaokun
    Mapping real world problems onto machine
    with several levels abstraction
    with real world limitations in mind
    

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12. Twitter: @doubaokun
    1. 1 CPU cycle 0.3 ns
    2. Main memory access 120 ns
    3. Goroutine 170 ns
    4. Swoole Coroutine 190 ns
    5. Linux OS context switch 1,000 ns
    6. Linux thread launch 5,000 ns
    7. Linux process launch 20,000 ns
    8. Per-thread stack is 8MB (ulimit -s)
    

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13. • Unpredictable external performance
    • Client side I/O
    • Server side I/O
    • Queue theory
    Twitter: @doubaokun
    

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14. Twitter: @doubaokun
    wait time
    utilization
    

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15. Twitter: @doubaokun
    Mapping real world problems onto machine
    with several levels abstraction
    with real world limitations in mind
    about management and structure
    

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16. Scaling up the power
    Twitter: @doubaokun
    

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17. Scaling up the power
    Twitter: @doubaokun
    

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18. = Scaling the concurrency
    Twitter: @doubaokun
    

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19. What is Concurrency?
    Twitter: @doubaokun
    

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20. Concurrency is managing multi-tasking
    Twitter: @doubaokun
    

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21. Concurrency is managing multi-tasking
    in both real world and machine world
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22. Twitter: @doubaokun
    

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23. What is blocking
    Twitter: @doubaokun
    

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24. Twitter: @doubaokun
    

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25. Blocking is sequential
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26. Blocking and sequential are the nature
    of human mind and machine
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27. Blocking and sequential are the nature
    of a single Execution Unit
    Twitter: @doubaokun
    

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28. What is blocking I/O
    Twitter: @doubaokun
    

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29. Twitter: @doubaokun
    

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30. Blocking I/O is the nature of machine
    Twitter: @doubaokun
    

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31. What is async I/O
    Twitter: @doubaokun
    

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32. Twitter: @doubaokun
    

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33. The nature of real world I/O
    Twitter: @doubaokun
    

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34. The nature of real world is better
    resources utilisation
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35. Mapping real world to machine
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36. Mapping real world to machines:
    Unlimited Execution Unit and I/O
    vs
    Limited resources and machines
    Twitter: @doubaokun
    

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37. Concurrency is hard
    Twitter: @doubaokun
    

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38. Concurrency models
    • Process
    • Process pool
    • Thread
    • Thread pool
    • Single thread async I/O
    • Light weight thread: Fiber / Coroutine / …
    Twitter: @doubaokun
    

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39. Concurrency is hard
    • Inefficient scaling
    • Race condition
    Twitter: @doubaokun
    

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40. https://unixism.net/2019/04/linux-applications-performance-introduction/
    Twitter: @doubaokun
    Performance of Concurrent I/O models
    

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41. Machine I/O Concurrency
    Twitter: @doubaokun
    

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42. Decoupling I/O and CPU
    Twitter: @doubaokun
    

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43. Async machine I/O
    Twitter: @doubaokun
    

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44. Twitter: @doubaokun
    

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45. Event based callbacks ?
    Twitter: @doubaokun
    

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46. not the nature of human mind
    Twitter: @doubaokun
    

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47. Async machine I/O should be
    abstracted
    Twitter: @doubaokun
    

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48. Understand the machine better
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49. Concurrency and Operating System
    Twitter: @doubaokun
    

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50. What is a function?
    Twitter: @doubaokun
    

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51. a sequence of instructions that
    takes inputs and returns outputs
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52. function add($a, $b) {
    return $a + $b;
    }
    Twitter: @doubaokun
    

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53. What is Context?
    Twitter: @doubaokun
    

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54. Twitter: @doubaokun
    

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55. Call Stack and Stack Frame
    Twitter: @doubaokun
    

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56. function add($a, $b) {
    return $a + $b;
    }
    function plus5($c, 5) {
    return add($c, 5);
    }
    Twitter: @doubaokun
    

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57. Twitter: @doubaokun
    

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58. What is context switch?
    Twitter: @doubaokun
    

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59. Twitter: @doubaokun
    

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60. History of multi-tasking in OS
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61. 1. No scheduler
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62. 2. Cooperative Scheduler
    Non-preemptive
    Twitter: @doubaokun
    

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63. 3. Preemptive timer interrupt
    scheduler
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64. Twitter: @doubaokun
    

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65. Twitter: @doubaokun
    

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66. Thread context switch can be
    expensive
    Twitter: @doubaokun
    

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67. Not scalable
    Twitter: @doubaokun
    

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68. Light weight thread
    Twitter: @doubaokun
    

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69. Light weight Execution Unit
    Twitter: @doubaokun
    

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70. Light weight Execution Unit
    provided by machine/library
    Twitter: @doubaokun
    

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71. Light weight Execution Unit
    provided by machine
    to map real world problems
    Twitter: @doubaokun
    

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72. Light weight Execution Unit
    provided by machine
    to map real world problems
    to execute real world tasks
    Twitter: @doubaokun
    

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73. What is Coroutine?
    Twitter: @doubaokun
    

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74. “Coroutines are computer components that
    generalise subroutines for non-preemptive multitasking,
    by allowing execution to be suspended and resumed.”
    - Wikipedia
    Twitter: @doubaokun
    

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75. “a type of functions that enables concurrency
    via cooperative multitasking”
    Twitter: @doubaokun
    

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76. Cooperative multi-tasking
    Twitter: @doubaokun
    

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77. Multi-tasking management strategy
    Twitter: @doubaokun
    

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78. On machine:
    User space yield and resume
    Twitter: @doubaokun
    

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79. 1
    3
    start
    2
    4
    Twitter: @doubaokun
    

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80. Twitter: @doubaokun
    

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81. Swoole
    Twitter: @doubaokun
    

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82. https://www.swoole.co.uk/
    https://github.com/swoole/swoole-src
    @php_swoole
    Coroutine-based concurrency library with PHP syntax
    Twitter: @doubaokun
    

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83. Twitter: @doubaokun
    

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84. Super fast
    Twitter: @doubaokun
    

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85. Super fast
    https://tsh.io/blog/swoole-is-it-node-in-php-or-am-i-wrong/
    Twitter: @doubaokun
    

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86. Super fast
    Twitter: @doubaokun
    

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87. Twitter: @doubaokun
    • Async I/O
    • Reuse states
    • Coroutine
    • Coroutine scheduler based on I/O
    

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88. Twitter: @doubaokun
    

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89. Swoole server
    Twitter: @doubaokun
    

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90. HTTP server with PHP Swoole
    Twitter: @doubaokun
    

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91. Server structure
    Twitter: @doubaokun
    

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92. Server structure
    Twitter: @doubaokun
    

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93. Swoole Coroutine Internal
    Twitter: @doubaokun
    

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94. Twitter: @doubaokun
    

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95. Use cases
    Twitter: @doubaokun
    

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96. Twitter: @doubaokun
    

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97. Common pitfalls
    Twitter: @doubaokun
    

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98. Twitter: @doubaokun
    Common pitfalls
    • Looking to run it on M$ Windows
    • Trying to run it with PHP-FPM
    • Stateless mind
    • Variable scope: super global, global, static, local variables
    • Blocking within Coroutine context
    • Exception handling
    • Exit
    

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99. Code samples
    Twitter: @doubaokun
    

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100. Coroutine
     Twitter: @doubaokun
     

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102. 1
     3
     start
     2
     4
     Coroutine yield and resume
     

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103. 2
     1
     3
     2
     Coroutine structure
     

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104. Server
     Twitter: @doubaokun
     

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105. Server response timeout
     

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106. Timer
     Twitter: @doubaokun
     

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107. Timer
     

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108. Client
     Twitter: @doubaokun
     

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109. HTTP Client
     

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110. Channel
     Twitter: @doubaokun
     

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112. Coroutine Pooling
     Twitter: @doubaokun
     

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115. Linux process
     Twitter: @doubaokun
     

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117. HashTable
     Twitter: @doubaokun
     

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119. Task worker
     Twitter: @doubaokun
     

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122. Coroutine Server
     Twitter: @doubaokun
     

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123. Twitter: @doubaokun
     

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124. Demo
     Twitter: @doubaokun
     

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125. https://www.swoole.co.uk/
     https://twitter.com/php_swoole
     https://github.com/swoole/swoole-src
     https://github.com/21days-dev/phpuk2020
     Thank you
     

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