Benchmarking a rake task

rake_benchmark.rb

# Put this in Rakefile (doesn't matter where)
require 'benchmark'

class Rake::Task
  def execute_with_benchmark(*args)
    bm = Benchmark.measure { execute_without_benchmark(*args) }
    puts "   #{name} --> #{bm}"
  end

  alias_method :execute_without_benchmark, :execute
  alias_method :execute, :execute_with_benchmark
end