Benchmarking the fibonacci sequence through an increasing number of iterations. Credit @tenderlove.

benchmark_example2.rb

require 'benchmark'

def fib n
  a = 0
  b = 1
  n.times { a, b = b, a + b}
  a
end

Benchmark.bm(10) do |x|
  [1, 10, 100, 1000, 10000].each do |n|
    x.report("fib #{n}") do
      n.times { fib(1000) }
    end
  end
end