gistfile1.txt

require 'benchmark'

n = 10
command = "sleep 1"

Benchmark.bm do |x|
  x.report do
    a = (1..n).collect { Thread.new { `#{command}` } }
    a.each { |t| t.join }
  end
  x.report do
    n.times do
      `#{command}`
    end
  end
  x.report do
    a = (1..n).collect { Thread.new { IO.popen(command) { |io| io.each { |l| l } } } }
    a.each { |t| t.join }
  end
end

#     user     system      total        real
# 0.000000   0.010000   0.060000 (  1.013273)
# 0.010000   0.000000   0.060000 ( 10.060332)
# 0.000000   0.010000   0.070000 (  1.013631)