Nesta palestra dada no TDC 2011, falei sobre I/O por eventos, comparação com a metodologia tradicional com threads, EventMachine, bibliotecas relacionadas e aplicações.

1. Alcançando Alta
Performance com
EventMachine

2. $ whoami

3. Vinícius Baggio Fuentes
@vinibaggio

4. outpost gem

7. EventMachine

8. EventMachine
Evented I/O ‘tá na moda’

9. Twisted
Goliath HTTPd
EventMachine
Apache Mina
JBoss Netty

10. Mas o que é isso?

11. Relembrando:
quais são os tipos de
I/O?

12. Maneiras de se fazer I/O
• Blocking I/O
• Nonblocking I/O
• Asynchronous ou Threaded I/O

13. C10K Problem
http://www.kegel.com/c10k.html

14. Evented I/O
vs
Threaded/Async I/O

15. Threaded HTTPd,
stupid edition

16. Threaded HTTPd, stupid edition
Main Process :80

17. Threaded HTTPd, stupid edition
Main Process :80 Client

18. Threaded HTTPd, stupid edition
Main Process :80 Client
Worker

19. Threaded HTTPd, stupid edition
Main Process :80
Worker :5938 Client

20. Threaded HTTPd, stupid edition
Main Process :80 Client
Worker :5938 Client

21. Threaded HTTPd, stupid edition
Main Process :80 Client
Worker :5938 Client
Worker

22. Threaded HTTPd, stupid edition
Main Process :80
Worker :5938 Client
Worker :5939 Client

23. Evented I/O,
stupid edition

24. Evented I/O, stupid edition
Main Process
Kernel

25. Evented I/O, stupid edition
:80
Main Process
Kernel

26. Evented I/O, stupid edition
ilo!
nqu ir!
Tra orm
Pod ed
Main Process
Kernel
File descriptor :80

27. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80

28. Evented I/O, stupid edition
zZ
zz
Client
Main Process
Kernel
File descriptor :80

29. Evented I/O, stupid edition
ACORDA! !! !!!!
Client
Main Process
Kernel
File descriptor :80

30. Evented I/O, stupid edition
Main Process
Client
Kernel
File descriptor :80

31. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

32. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

33. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

34. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

35. Evented I/O, stupid edition
ACORDA, !! !!!!
P&$#A!
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

36. Evented I/O, stupid edition
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

37. Evented I/O, stupid edition
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

38. Evented I/O, stupid edition
zZ
zz
Main Process
Kernel
File descriptor :80
File descriptor :5339 Client

39. PRE-RI-GO!

40. Callbacks, callbacks,
callbacks!

41. O EventMachine facilita
tudo isso!

42. Como funciona?
Reactor pattern
1. Recurso
2. Multiplexador de eventos
3. Handlers

43. Exemplo 1

44. http://www.youtube.com/watch?v=oewlFNIYNM8

45. Voltando ao Exemplo 1
require 'eventmachine'
module EchoServer
def post_init
puts "Someone connected to the server"
end
def receive_data data
send_data "Data received: #{data}"
end
end
EventMachine::run {
EventMachine::start_server "127.0.0.1", 8081, EchoServer
}

46. Como funciona?
EventMachine = Reactor +
Facilidades para:
➡Rede
➡Teclado
➡Timers
...

47. Voltando ao Exemplo 1
require 'eventmachine'
module EchoServer
def post_init
puts "Someone connected to the server"
end
def receive_data data
send_data "Data received: #{data}"
end
end
EventMachine::run {
EventMachine::start_server "127.0.0.1", 8081, EchoServer
}

48. post_init

49. receive_data

50. unbind

51. Voltando ao Exemplo 1
require 'eventmachine'
module EchoServer
def post_init
puts "Someone connected to the server"
end
def receive_data data
send_data "Data received: #{data}"
end
end
EventMachine::run {
EventMachine::start_server "127.0.0.1", 8081, EchoServer
}

52. E operações
lentas?

53. defer

54. Mas isso é só o
básico, dá trabalho
de implementar
meu protocolo?

55. Bem, existem algumas
bibliotecas...

56. • SMTP Client • XMPP
• LineAndText (teclado) • Redis
• HTTPClient • MongoDB
• HTTPServer • CouchDB
• MySQL • Beanstalkd
• RabbitMQ (AMQP • Proxy
compat.) • Cassandra
• SMTP Server • Solr
• PostgreSQL • Amazon S3
• Memcache • ...

57. A grande vantagem do
Event Machine é a facilidade

58. Cada lib tem seus próprios
eventos

59. Caso real de uso

60. Página que, sob carga,
simplesmente não respondia

61. SWAP?

62. Não.

63. SQL?

64. Era bem complexo.
Mas rodava rápido localmente e
com o mesmo dataset

66. Então como?

68. em-proxy to the rescue!

69. Client
em
proxy
Production Staging

70. Client
em
proxy
Production Staging

71. Client
em
proxy
Production Staging

72. Client
em
proxy
Production Staging

73. Client
em
proxy
Production Staging

74. http://www.youtube.com/watch?v=n0OOtMG7wGA

75. Análises e alterações para
verificar e corrigir o
comportamento

76. O proxy não introduziu
latências que mereçam
atenção

77. Usos
Filtrar Spam fazendo proxy SMTP

78. Usos
Clientes HTTP (ex. Faraday)

79. Usos
Proxies para qualquer serviço

80. Usos
Monitorar arquivos

81. Usos
o céu é o limite!

82. Fim!
Perguntas?
@vinibaggio
vinibaggio@gmail.com
vinibaggio.net