Ruby micro benchmark code to test across implementations

micro_ruby_benchmark.rb

def bench name
  warmup = yield
  puts "Warming up '##{name}'"
  GC.start
  first = yield
  GC.start
  second = yield
  GC.start
  third = yield

  puts "Average of 3 runs: #{(first + second + third) / 3}"
  puts "=" * 50
end

def sum count
  num = (1..count).map { |n| n }
  start = Time.now
  num.inject(0) { |sum, n| sum + n }
  Time.now - start
end

def md5 count, threads=nil
  require 'parallel'
  require 'digest/md5'
  if threads
    num = (1..count).map { |n| n }
    start = Time.now
    Parallel.map(num, :in_threads => threads) { |n| Digest::MD5.hexdigest n.to_s }
    Time.now - start
  else
    i = 0
    start = Time.now
    while i < count
      i += 1
      Digest::MD5.hexdigest i.to_s
    end
    Time.now - start
  end
end

def arithmetic count
  i = 0
  start = Time.now
  while i < count
    i += 1
    count + count
    count - count
    count / count
    count * count
  end
  Time.now - start
end

def array_shovel count
  i = 0
  start = Time.now
  array = []
  while i < count
    i += 1
    array << i
  end
  Time.now - start
end

def array_set_ops count
  i = 0
  set1 = (1..11_000).map { |n| n }
  set2 = (9_000..22_000).map { |n| n }
  start = Time.now
  while i < count
    i += 1
    set1 & set2 # Union
    set1 | set2 # Intersection
    set1 - set2 # Difference
  end
  Time.now - start
end

def set_operations count
  require 'set'
  i = 0
  set1 = Set.new (1..11_000).map { |n| n }
  set2 = Set.new (9_000..20_000).map { |n| n }
  start = Time.now
  while i < count
    i += 1
    set1.union set2
    set1.intersection set2
    set1.difference set2
  end
  Time.now - start
end

def array_filtering count
  i = 0
  array = (1..count).map { |n| n }
  start = Time.now
  while i < count
    i += 1
    array.reject { |n| n != count }
    array.select { |n| n != count }
  end
  Time.now - start
end

bench("sum 10 million elements") { |i| sum 10_000_000 }
bench("md5 200k elements with NO threading") { |i| md5 200_000 }
bench("md5 200k elements with 1 thread") { |i| md5 200_000, 1 }
bench("md5 200k elements with 2 threads") { |i| md5 200_000, 2 }
bench("md5 200k elements with 3 threads") { |i| md5 200_000, 3 }
bench("md5 200k elements with 4 threads") { |i| md5 200_000, 4 }
bench("arithmetic 10 million elements") { |i| arithmetic 10_000_000 }
bench("array_shovel 10 million elements") { |i| array_shovel 10_000_000 }
bench("set_operations 100 times") { |i| set_operations 100 }
bench("array_set_ops 100 times") { |i| array_set_ops 100 }
bench("array_filtering 2000 times") { |i| array_filtering 2000 }