The document presents an overview of runtime and concurrency in Go, discussing key concepts such as concurrency, parallelism, and the lifecycle of Go binaries. It covers the mechanics of goroutines, coroutines, and green threads while emphasizing their differences and execution models. It also includes quizzes related to goroutines to engage the audience in understanding concurrency and parallelism better.

1. Runtime & Concurrency
in Go
V N Nikhil Anurag
GopherCon Singapore 2017

2. Agenda
Concurrency & Parallelism
Lifecycle of Binaries
Coroutines & Green Threads
Goroutines
Pop Quiz

3. Concurrency & Parallelism

4. Concurrency Parallelism
Concurrency is about dealing with
lots of things at once.*
Parallelism is about doing lots of
things at once.*
* https://blog.golang.org/concurrency-is-not-parallelism

5. Lifecycle of Binaries

6. Lifcycle
Of
Binaries
Lifecycle of Interpreted Languages
Lifecycle of a Go Binary

7. Lifecycle of Interpreted Languages (VM)
Single Executable
Virtual
Machine
Byte Code

8. Lifecycle of Interpreted Languages (VM)
(VM + Application Code) * No. of Workers
Virtual
Machine
Byte Code
Virtual
Machine
Byte Code
Virtual
Machine
Byte Code

9. Lifecycle of Interpreted Languages (VM)
(VM + Application Code) * No. of Workers
This is required because...
Virtual
Machine
Byte Code
Virtual
Machine
Byte Code
Virtual
Machine
Byte Code

10. Global Interpreter Lock

11. Task to Run
GIL
Func 1 Func 2 Func 3 Func 4
Task
1
Task
2
Task
4
Task
3
?

12. A Go Binary
Program
OS
Architecture
Runtime

13. A Go Binary
What about multiple requests?
Program
OS
Architecture
Runtime

14. ♫We don’t need no Multiple Instances♫

15. A Go Binary
Program
OS
Architecture
Runtime

16. Coroutines & Green Threads

17. No one likes Threads.

18. Coroutines

19. Coroutines
Event Loop
Components of a Coroutine
Life of a Coroutine

20. Coroutines
EVENT LOOP

21. Coroutines
Task
1
Task
2
Task
6
Task
4
Task
10
EVENT LOOP

22. Components of Coroutine

23. Coroutines
?
??
Components of Coroutine

24. Coroutines
Yield
??
Components of Coroutine

25. Coroutines
Yield
?Await
Components of Coroutine

26. Coroutines
Yield
Await Result
Components of Coroutine

27. Life of a Coroutine

28. Coroutines

29. Coroutines
√

30. Coroutines
√
√

31. Coroutines
√
√

32. Coroutines
√
√

33. Coroutines
√
√
√

34. Coroutines
√
√
√
X

35. Coroutines
√
√
√
X √

36. Coroutines
√
√
√
X √

37. Coroutines
√
√
√
X √
√

38. Coroutines

39. Coroutines
√
√
√
√
√
√

40. Coroutines - Python

41. Green Threads
They are a lot like Coroutines

42. Green Threads
THREAD 1

43. Green Threads
THREAD 1 THREAD 2

44. Green Threads
CORE 1
THREAD 1
CORE 1
THREAD 2
CORE 2?
THREAD 1?

45. Threads implemented by Runtime (and across Cores?)
Parallelism(?) by Runtime
Green Threads
Spawned by Runtime
Concurrency handled by User

46. Green Threads - Python (greenlet)

47. Goroutines

48. Goroutines

49. Goroutines
THREAD 1 THREAD 2

50. Goroutines

51. Goroutines

52. Goroutines
???

53. Goroutines

54. Goroutines
Spawned by Runtime

55. Parallelism &
execution by Runtime
Goroutines
Spawned by Runtime

56. Implemented across Threads
& Core
Parallelism &
execution by Runtime
Goroutines
Spawned by Runtime

57. Implemented across Threads
& Core
Parallelism &
execution by Runtime
Concurrency handled by User
Goroutines
Spawned by Runtime

58. Goroutines

59. Pop Quiz

60. Goroutine Pop Quiz
Q: Since they are running across
multiple threads, does failure in one
goroutine halt the program?

61. Goroutine Pop Quiz
Q: Since they are running across
multiple threads, does failure in one
goroutine halt the program?
YES!

62. Goroutine Pop Quiz
Q: Will running CPU intensive tasks in
goroutines block them?

63. Goroutine Pop Quiz
Q: Will running CPU intensive tasks in
goroutines block them?
MAYBE?

64. I/O Bound == Concurrency
CPU Bound == Parallelism

65. Goroutines:
Coroutines + Green Threads
+ Much Much More!

66. • Twitter - @last_ent
• Github – github.com/last-ent