RubyConf.ph 2014 - ZOMGSCALE! With Celluloid & JRuby

1. zomgscale! with Celluloid and JRuby Ben Lovell
2. benlovell _j
3. 113581334398839860922 !
7. “I HAVE KILLED, AND I WILL KILL AGAIN”
26. HEY LADIES
27. ❤️
30. zomgscale! with Celluloid and JRuby Ben Lovell
31. Moore’s Law
33. I don’t like bungee jumping... ! ...but I do like skiing Roger Moore
35. every few years CPU clocks have doubled
36. but recently this growth has stalled
37. cores ++++++++
38. the free lunch is over Herb Sutter
39. harness the POWER in those cores
40. ?
41. concurrency parallelism
42. so there’s a difference?
43. concurrent!
44. parallel?
46. processes or threads
47. processes memory constraints communication x cores == x processes?
48. processes what about fork(2) and CoW friendly GC ?
49. not CoW friendly
50. threads shared state locks and lock granularity race conditions can be hard to reason about
51. zomg! I love multithreaded code - NOBODY EVER
54. so what’s up with MRI?
55. well, nothing but...
56. GIL
57. some things the GIL is responsible for...
58. San Francisco Bay oil spillage
59. ...maritime disasters
60. THANKS, GIL!
61. GIL
62. MRI not so bad if you’re I/O bound
63. MRI but what about computation?
64. meh. thread-level parallelism is available right now! ...just not with MRI
66. rubinius 2.0.0 due for release 2042 OLD SLIDE ALERT!
67. so now that we have truly parallel threads is the problem solved?
68. ! ! rules of threading
69. Don’t do it!
70. If you must do it don’t share data across threads
71. If you must share data across threads don’t share mutable data
72. If you must share mutable data across threads synchronise access to this data
73. don’t communicate by sharing memory... ! ...share memory by communicating go
75. painless multithreaded programming for ruby
76. Tony Arcieri Tim Carey-Smith Ben Langfeld @bascule @halorgium @benlangfeld The Maintainers
79. a concurrent object oriented programming framework which lets you build multithreaded programs out of concurrent objects just as easily as you build sequential programs out of regular objects
81. based upon the actor model
82. actor model first proposed way back in 1970
83. actor model actors are isolated within lightweight processes
84. actor model actors possess identity
85. actor model absolutely no shared state
86. actor model actors don’t need to compete for locks
87. actor model are sent messages asynchronously
88. actor model messages are buffered by a mailbox
89. actor model the actor works off each message sequentially
90. actor model has implementations in many languages
95. celluloid actors automatically synchronize state
96. 1 class Actor! 2 attr_reader :counter! 3 ! 4 def initialize! 5 @counter = 0! 6 @mutex = Mutex.new! 7 end! 8 ! 9 def increment! 10 @mutex.synchronize do! 11 @counter += 1! 12 end! 13 end! 14 end!
97. with celluloid the same example...
98. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 attr_reader :counter! 6 ! 7 def initialize! 8 @counter = 0! 9 end! 10 ! 11 def increment! 12 @counter += 1! 13 end! 14 end!
100. celluloid actors are active objects living within threads
101. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 end! 6 ! 7 actor = Actor.new! 8 actor.inspect! 9 #=> <Celluloid::ActorProxy(Actor:0x3feaecbb38e0)>! 10 ! 11 Thread.main! 12 #=> <Thread:0x007f86290b8ce8 run>! 13 ! 14 actor.thread! 15 #=> <Thread:0x007f862ad27a78 sleep>!
102. 1 module Celluloid! 2 module ClassMethods! 3 # Create a new actor! 4 def new(*args, &block)! 5 proxy = Actor.new(allocate, actor_options).proxy! 6 proxy._send_(:initialize, *args, &block)! 7 proxy! 8 end! 9 #...! 10 end! 11 #...! 12 end!
103. celluloid actors messages you send are buffered via the actor’s mailbox...
104. celluloid actors ... until the actor is ready to act upon them
105. ______________! < ETOOMANYACTS >! --------------! \ ^__^! \ (oo)\_______! (__)\ )\/\! ||----w |! || ||! !
106. celluloid actors no pattern matching just regular messages
107. celluloid actors poll their mailbox in a message loop
108. 1 class Actor! 2 # Wrap the given subject with an Actor! 3 def initialize(subject, options = {})! 4 @subject = subject! 5 @mailbox = options[:mailbox] || Mailbox.new! 6 @running = true! 7 ! 8 @thread = ThreadHandle.new(:actor) do! 9 setup_thread! 10 run! 11 end! 12 #...! 13 end! 14 #...! 15 end!
109. 1 class Actor! 2 def run! 3 #...! 4 while @running! 5 if message = @mailbox.receive(timeout_interval)! 6 handle_message message! 7 else! 8 # No message indicates a timeout! 9 @timers.fire! 10 @receivers.fire_timers! 11 end! 12 end! 13 #...! 14 shutdown! 15 end! 16 end!
110. celluloid actors act upon messages sequentially
111. what about ordering? no guarantees
112. celluloid actors dispatch calls within fibers
113. fibers? cooperative lightweight user space some gotchas...
114. celluloid actors can dispatch synchronously
115. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 sleep 2! 8 puts "42"! 9 end! 10 end! 11 ! 12 actor = Actor.new! 13 actor.compute_all_the_things! 14 puts "done!"! ! #=> 42! #=> done!! blocking
116. celluloid actors can dispatch asynchronously
117. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 sleep 2! 8 puts "42"! 9 end! 10 end! 11 ! 12 actor = Actor.new! 13 actor.async.compute_all_the_things! 14 puts "done!"! 15 ! 16 #=> done!! 17 #=> 42! returns immediately
118. celluloid actors can perform tasks in futures
119. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 sleep 2! 8 "42"! 9 end! 10 end! 11 ! 12 actor = Actor.new! 13 future = actor.future.compute_all_the_things! 14 puts "done!"! 15 puts future.value! 16 ! 17 #=> done!! 18 #=> 42! returns immediately blocks until a value is yielded
120. celluloid actors are accessible by reference or name
121. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 sleep 2! 8 puts "42"! 9 end! 10 end! 11 ! 12 actor = Actor.new! 13 Celluloid::Actor[:foo] = actor! 14 ! 15 actor.inspect! 16 #=> <Celluloid::ActorProxy(Actor:0x3feb3ec11308)>! 17 Celluloid::Actor[:foo].inspect! 18 #=> <Celluloid::ActorProxy(Actor:0x3feb3ec11308)>!
122. celluloid actors are fault tolerant ... let it crash!
123. 1 require "celluloid/autostart"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 puts "42"! 8 end! 9 ! 10 def zomg_crash! 11 raise "derp!"! 12 end! 13 end! 14 ! 15 supervisor = Actor.supervise_as :foo! 16 ! 17 begin! 18 Celluloid::Actor[:foo].zomg_crash! 19 rescue! 20 puts "whoops"! 21 end! 22 ! 23 Celluloid::Actor[:foo].compute_all_the_things! 24 ! 25 #=> whoops! 26 #=> 42! crash the actor fresh actor take care of me!
124. celluloid actors can be arranged as pooled workers
125. 1 require "celluloid"! 2 ! 3 class Actor! 4 include Celluloid! 5 ! 6 def compute_all_the_things! 7 sleep 1! 8 puts "42"! 9 end! 10 end! 11 ! 12 pool = Actor.pool! 13 ! 14 4.times { pool.compute_all_the_things }! 15 ! 16 #=> 42! 17 #=> 42 and so on...! size*cores load up the workers
126. there’s more timers links supervision groups pub/sub conditions
127. that low hanging fruit? yeah, about that...
128. but there is one tip! blocking I/O... don’t
130. an event-driven IO system for building fast, scalable network applications that integrate directly with celluloid actors
132. unlike certain other evented I/O systems which limit you to a single event loop per process Celluloid::IO lets you make as many actors as you want system resources permitting
135. a distributed extension to celluloid which provides distributed and concurrent objects for ruby that are both robust and fault-tolerant
137. a fast non-blocking and evented web server. Thanks to celluloid, Reel works great for multithreaded applications and provides traditional multithreaded blocking IO support too.
138. EXPERIMENTAL or broken as it is known outside of OSS
139. to summarise...
140. the future of ruby concurrency and parallelism?
141. thanks! @benlovell ?