From: 7stud -- <dolgun@...>
Date: 2007-10-09T17:35:38+09:00
Subject: Re: thread problem.....

Michael Bevilacqua-Linn wrote:
> 1.) The only way threads get you a speedup is when you write your code 
> in
> such a way that sections of it can be executed in parallel so you can 
> take
> advantage of multiple cores (or processors).
> 
> 2.) The current version of Ruby only supports green threads anyhow.  So 
> even
> if you did have multiple cores, you wouldn't get a speedup.
> 
> MBL

Then perhaps you could explain the output of this program:

require 'rtiming'  #a simple program that times methods

def test1
  threads = []

  2.times do |i|
  threads[i] = Thread.new do
    sleep(2)
    puts "task #{i+1} finished"
  end
  end

  threads.each do |t|
    t.join
  end
end

def test2
  sleep(2)
  puts "task 1 finished"

  sleep(2)
  puts "task 2 finished"
end

puts timer(:test1, 1)
puts timer(:test2, 1)


--output:---
task 2 finished
task 1 finished
Method exec time(1 loops): 2.010791 total
task 1 finished
task 2 finished
Method exec time(1 loops): 4.000226 total
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