1. Scala Erlang
Beijing 2010.04
Caoyuan (NetBeans Dream Team Member)
http://blogtrader.net
@dcaoyuan

2. • (
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3. •
• CPU
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•
•
•
•

4. -
• 1206
• 103 x1.5 =155 6
• 6144 CPU 5120 GPU
•
• 1280
• 1280
• 3 16
• CPU 60%

5. •
• Fortress Erlang Scala => Scala
•
•
• DSL
• -
• Map-Reduce, Fork-Join
•

6. Actor Erlang Scala
Erlang Scala Actor
• Erlang
• Erlang VM Actor
•
• Scala
• Actor JVM
• actor

7. Actor - Actor
Actor
• Actors
actor ! ChangeYourPosition
Pid ! change_your_position
• Actors
val a = actor { loop(I) ->
def loop(i: Int): Unit = receive
react { I -> I, loop(I + 1);
case i: Int => loop(i + 1) exit -> io:format(“~p~n”, [I])
case Exit => println(i) end
} end
loop(0) Pid = spawn(fun loop/1, [0])
}
•
• Actor
• loop (Scala Erlang) (Scala)
• Actors

8. Actor
Actor OO
•
• OO
• Actor
• (immutable)
•
•
• Actor
• Actor
Actor
• Actor
Actor Actor

9. Actor
Actor
•
•
•
Actor
CPU
•

10. Actor
CPU

11. Actor – vs
Actor
Actor CPU
Actors CPU

12. JVM
Scheduler
•
• IO
• CPU

13. Scala JVM Actor
Scheduler
• Actor Object
• Actor
• Actor
• Actor
Actor
• Actors Actors
• Scala IO
IO Actor

14. Erlang Actor Process
Scheduler
• Erlang Actor Process
• Process
• Process
• Process
• Erlang IO Process
IO

15. • Actor
 Actors Actor
•

sleep IO

•
Scala Actor NIO

16. Erlang vs Scala –
• Erlang Process
• Process
• Process
• Process CPU
Process
• log
 2-core 140 process 200 process
CPU 1 / 200 * 2 Core = 1%
 8-core 700 process 980 process
CPU 1 / 980 * 8 Core = 0.82%

17. Erlang vs Scala –
• Scala Actor
• Actor
Actors
•
Actor
•
• Actor

18. Erlang vs Scala –
• Erlang Process
•
• (GC )
• ( )
• VM (
)
•
• ( )

19. Erlang vs Scala –
• Scala Actor
Erlang
•
•
• VM VM
•
• JVM
•

20. Erlang vs Scala –
object ThreadRing {
val (nTokens, nProcs) = (20000, 10000)
def main(args: Array[String]) {
val last= Ring(null, 1)
val h = Range(nProcs, 2, -1).foldLeft(last){(acc, i) => Ring(acc, i)}
last.next = h
h ! nTokens
}
case class Ring(var next: Ring, id: Int) extends Actor {
start
def act = loop {
react {
case 1 =>
println("Done")
println(id)
System.exit(0)
case token: Int =>
next ! token - 1
println(token)
//fib(N_FIB)
}
}
}
}

21. Erlang vs Scala –
-module(threadring).
-export([main/0, ring/2]).
-define(N_TOKENS, 20000).
-define(N_PROCS, 10000).
main() ->
start(?N_TOKENS).
start(NToken) ->
H = lists:foldl(fun(Id, Pid) ->
spawn(threadring, ring, [Id, Pid])
end, self(), lists:seq(?N_PROCS, 2, -1)),
H ! NToken,
ring(1, H).
ring(Id, Pid) ->
receive
1 ->
io:fwrite(”~p~n", [done]),
io:fwrite("~b~n", [Id]),
erlang:halt();
Token ->
Pid ! Token - 1,
io:fwrite("~b~n", [Token]),
//fib(?N_FIB),
ring(Id, Pid)
end.

22. Erlang vs Scala –FP OO+FP
• Erlang
•
• Process
•

23. Erlang vs Scala –FP OO+FP
• Scala OO+FP
•
• Actor
Actors
• Actor
•

24. Q&A
Scala