Ruby Concurrency & ThreadsAnup Nivargi

I <3 Ruby!

Concurrency V Parallelism

Ruby ImplementationsMRI, JRuby, Rubinius etc..

Threads In Ruby

thread_example.rb

def thread1 100.times do |i| puts "In Thread 1" endend

def thread2 100.times do puts "In Thread 2" endend

t1 = Thread.new { thread1 }t2 = Thread.new { thread2 }

t1.joint2.join

CPU Intensive Tasks

factorial.rb

require 'benchmark'

def factorial_with_range(range) (1..range).to_a.each_slice(range/4).to_a.each do |elements| elements.each {|element| factorial(element) } endend

def factorial_with_range_threaded(range) threads = [] (1..range).to_a.each_slice(range/4).to_a.each do |elements| threads << Thread.new do elements.each{|element| factorial(element) } end end threads.each(&:join)end

factorial.rb (contd)

def factorial(n) (1..n).to_a.inject(:*)end

Benchmark.bm(30) do |bm| [4000, 5000].each do |num| bm.report("Single Threaded #{num}") do factorial_with_range(num) end

bm.report("Multi Threaded #{num}") do factorial_with_range_threaded(num) end endend

Ruby MRI Benchmarks

user system total realSingle Threaded 4000 10.230000 0.100000 10.330000 ( 10.419738)Multi Threaded 4000 10.340000 0.330000 10.670000 ( 10.770526)Single Threaded 5000 18.960000 0.490000 19.450000 ( 19.601181)Multi Threaded 5000 19.120000 0.730000 19.850000 ( 20.012569)

Rubinius Benchmarks

user system total realSingle Threaded 4000 6.228000 0.139000 6.367000 ( 6.413544)Multi Threaded 4000 0.003000 0.000000 0.003000 ( 4.565215)

Single Threaded 5000 11.519000 0.306000 11.825000 ( 11.937241)Multi Threaded 5000 0.002000 0.000000 0.002000 ( 9.129658)

Why?

GIL or GVLin Ruby MRI

But, there is a catch!

IO Intensive Task

server.rb

require "webrick"

server = WEBrick::HTTPServer.new :Port => 8000

server.mount_proc "/" do |req, res| sleep 1 res.body = "Hello World"end

trap 'INT' do server.shutdown end

server.start

service.rb

require "benchmark"require "net/http"

def fetch(count) uri = URI.parse("http://localhost:8000/") threads = [] count.times do threads << Thread.new do Net::HTTP.get_response(uri) end end threads.each(&:join)end

Benchmark.bm(30) do |bm| bm.report("IO Service"){ fetch(20) }end

Rubinius Benchmarks

user system total realIO Service 0.014000 0.002000 0.016000 ( 1.037461)

Ruby MRI Benchmarks

user system total realIO Service 0.050000 0.030000 0.080000 ( 1.070662)

Ahhhh!

Threading Caveats

Conclusion

Online References

Code : https://github.com/anupnivargi/experiments/tree/master/threads

https://blog.engineyard.com/2013/ruby-concurrency

http://speakmy.name/2013/04/02/concurrent-programming-and-threads-in-ruby-reading-list/

https://blog.engineyard.com/2011/ruby-concurrency-and-you

http://merbist.com/2011/02/22/concurrency-in-ruby-explained/

Questions?Anup Nivargi

@therealnoopanupnivargi@gmail.com

Thank You!