ruby_in_parallel.rb

require 'rubygems'
require 'parallel'  #http://github.com/grosser/parallel

$stdout.sync = true # Auto-flush for interactive I/O


def slow_action
  def fibo(n)
    0 == n ?  0 :
    1 == n ?  1 :
              fibo(n-1) + fibo(n-2)
  end

  fibo(26)
end

puts "-------------------------------------------------------"
puts "TOTAL TIME SPENT = #{start = Time.now ; slow_action ; Time.now - start}, for 1 process in solo"
puts "-------------------------------------------------------\n\n"

(1..5).each do |nof_processes|
  start_all = Time.now
  results = Parallel.in_processes(nof_processes) do |i|
    start=Time.now
    slow_action
    #sleep 2
    puts "task [#{i}] took #{Time.now-start}"
  end
  puts "-------------------------------------------------------"
  puts "TOTAL TIME SPENT = #{Time.now - start_all}, for #{nof_processes} processes in parallel"
  puts "-------------------------------------------------------\n\n"
end
# 
(1..5).each do |nof_threads|
  start_all = Time.now
  results = Parallel.in_threads(nof_threads) do |i|
    start=Time.now
    slow_action
    #sleep 2
    puts "task [#{i}] took #{Time.now-start}"
  end
  puts "-------------------------------------------------------"
  puts "TOTAL TIME SPENT = #{Time.now - start_all}, for #{nof_threads} threads in parallel"
  puts "-------------------------------------------------------\n\n"
end
__END__

Running “untitled”…
ruby 1.8.6 (2007-09-24 patchlevel 111) [i686-darwin9.2.2]
Theme:  
-------------------------------------------------------
TOTAL TIME SPENT = 1.808199, for 1 process in solo
-------------------------------------------------------

task [0] took 1.776081
-------------------------------------------------------
TOTAL TIME SPENT = 1.792507, for 1 processes in parallel
-------------------------------------------------------

task [0] took 1.966382
task [1] took 2.007124
-------------------------------------------------------
TOTAL TIME SPENT = 2.031983, for 2 processes in parallel
-------------------------------------------------------

task [1] took 2.925465
task [0] took 2.972259
task [2] took 2.956607
-------------------------------------------------------
TOTAL TIME SPENT = 2.998156, for 3 processes in parallel
-------------------------------------------------------

task [1] took 3.896803
task [2] took 3.925455
task [0] took 3.951028
task [3] took 3.986664
-------------------------------------------------------
TOTAL TIME SPENT = 4.042733, for 4 processes in parallel
-------------------------------------------------------

task [0] took 4.978787
task [4] took 4.978394
task [1] took 5.015142
task [2] took 5.001246
task [3] took 5.048229
-------------------------------------------------------
TOTAL TIME SPENT = 5.098819, for 5 processes in parallel
-------------------------------------------------------

task [0] took 1.811343
-------------------------------------------------------
TOTAL TIME SPENT = 1.811851, for 1 threads in parallel
-------------------------------------------------------

task [0] took 3.670152task [1] took 3.665148

-------------------------------------------------------
TOTAL TIME SPENT = 3.685674, for 2 threads in parallel
-------------------------------------------------------

task [2] took 5.712594
task [0] took 5.794754
task [1] took 5.895118
-------------------------------------------------------
TOTAL TIME SPENT = 5.921765, for 3 threads in parallel
-------------------------------------------------------

task [0] took 9.610279
task [3] took 9.71832task [1] took 9.722265

task [2] took 9.741574
-------------------------------------------------------
TOTAL TIME SPENT = 9.809111, for 4 threads in parallel
-------------------------------------------------------

task [0] took 9.586654task [2] took 9.613722task [3] took 9.630558task [1] took 9.630701



task [4] took 9.662679
-------------------------------------------------------
TOTAL TIME SPENT = 9.763632, for 5 threads in parallel
-------------------------------------------------------

copy output
Program exited with code #0 after 49.97 seconds.