Revised from https://github.com/ruby/ruby/pull/1921

loop.rb

if RubyVM::MJIT.enabled?
  RubyVM::MJIT.pause
end

require 'erb'
require 'shellwords'

methods = Integer(ARGV[0] || 1)
sleep_seconds = methods * 0.15
loop_count = (250000000.0 / methods).to_i

src = ERB.new(<<-'erb', nil, '%').result(binding)
% methods.times do |i|
def call<%= i %>() nil end
call<%= i %>; call<%= i %>
% end
if RubyVM::MJIT.enabled?
  RubyVM::MJIT.pause
end
i = 0
before = Process.clock_gettime(Process::CLOCK_MONOTONIC)
while i < <%= loop_count %>
  <%= methods.times.map { |i| "call#{i}; " }.join('') %>
  i += 1
end
after = Process.clock_gettime(Process::CLOCK_MONOTONIC)
puts((after - before).to_s)
erb

puts "\n```\n#{src}```\n\n"

results = []

3.times do
  if RubyVM::MJIT.enabled?
    cmd = [RbConfig.ruby, '--disable-gems', '--jit-min-calls=2', '--jit-verbose=1', '--jit-max-cache=10000', '-e']
  else
    cmd = [RbConfig.ruby, '--disable-gems', '-e']
  end
  puts "+ #{cmd.shelljoin} ..."
  result = IO.popen([*cmd, src], &:read)
  results << result
  puts "Result: #{result}\n"
end

puts "Avg: #{results.map(&:strip).map(&:to_f).inject(&:+) / results.size.to_f}"